I've been to Lisbon seven times. I am from NW Spain and it is 300 miles from my hometown (sorry if my english is not perfect).
I'll be there in october (from 8th tl 12th) at the same hotel. I've been there three times before, and it is a great deal. It is not in the main tourist downtown area, but it is in the middle of the business area, between an hospital and RTP (National Portuguese TV) building so, it is a safe and quite area, even at night. The hotel is 1,5 miles away from the tourist area, but you can find a subway station 100 m. from the entrance, and iit'll take you downtown in 10 minutes. Lisbon subway is cheap (1$) and clean, and from 07 in the morning to 10 or 11 in the night is safe. You can also taxe a a taxi cab, but Lisbon taxi drivers are real masters cheating tourists. you can be almost sure they'll use the long way to your destination and they'll charge you at least 4 times the real value of the ride. Even if you know the city, they will cheat you. Use the subway or, in downtown, the old tramcars.
The hotel is a good high quality 4*. It is near the main traffic axis, but it is in a small street, so you are well located and far from the traffic noise. Rooms are comfortable and spacious, abd they serve a good breakfast. Near the hotel, you'll find several restaurants, cervejarias (beer bars) and cafes.
If you are planning to book a tourist tour, I suggest you to better rent a car. It is much cheaper and you'll avoid some hyper-touristic attractions. If you rent a car you have loads of places to visit near the city to know the real Portugal and most of them are not included in tourist tours. Sintra (15 miles west) is one of the most beautiful towns in Europe. Fishermen towns as Cascais and Ericeira (both west of Lisbon) are also tourist spots and nice places to visit, specially in autumn. Near Sintra and Cascais you'll find Estoril, a beach town with the bigger Casino in Portugal. 10 miles north from Sintra you'll find Mafra, the biggest monastery in Portugal, with 666 rooms. Obidos, a well-preserved walled medieval town is 60 miles north and near another nice seaport, Peniche, wher you'll find beautiful beaches and cliffs. Some 20 miles north of Obidos you'll find Nazar��, another sea town, with its old town (called Sitio) in the top of a 600 ft. cliff. If you like gothic churches, you should go to Santarem 40 miles north of Lisbon. But if you prefer to visit another portuguse main city, you can go to Coimbra, it'll take you an hour and a half from Lisbon, but it is a worthy visit. Coimbra is really nice. It has the oldest university in Portugal and several palaces and nice churches. You'll find the real Portugal there. Of course, it is is a cheaper place, specially to eat, and you'll find great food there. It is the confectionery capital city of the country, so if you go there you have to try Papos de Freiras (Nun's Bellies), Pasteis de Laranja (orange biscuits) and many others.
If you prefer to go south, you have to visit Arr��bida Mountains National Park, 25 miles from Lisbon. It is a mountain range with impressive cliffs falling into the deep-blue sea and lovely hidden beaches and villages. You'll find superb sights over Setubal Bay (one of the most beautiful bays in the world) and Troia beaches. Near here, at Cape Espichel, you'l find sandy beaches, cliffs and dinosaur footprints.The main town in this area is Sesimbra, where you can find some of the best seafood restaurants in Portugal. If you visit Palmela, the other town of the area, you have to go to its medieval castle, one of the best hotels in Portugal, with an excellent restaurant and bar. In this area you should buy some Arr��bida Cheese (one of the best in Portugal) and Moscatel de Setubal (sweet wine from Setubal. You'll find it white or red). Another worthy visit in the southern area is ��vora, 75 miles SW from Lisbon, one of the preferred places for portuguese tourists. It is the main city in the southern inland, Alentejo, the poorest part of the country. You'll be surprised by its beautifull cathedral, city walls, monasteries and palaces and specially by its roman temple. It is really a nice place, and it is just an hour and a half from Lisbon. If you like strong sheep cheeses, this is the place to go. Try Queijinhos de Evora (Evora small cheeses).
If you book a tourist tour, it'll cost you at leat 50-75 $ p/p (a one day tour) and they'll show you just Sintra, some tourist points in Lisbon city, a false Fado Restaurant, maybe Estoril and less more. Believe me, it is a better idea to rent your own car. Portugal is a quite country, you won't find much traffic, except at Lisbon. You can't forget it is a capital and business city. Avoid rush hours (07:30 to 09:30 in the morning, 13:00 to 15:00 in the afternoon and 19:00 to 20:30 in the evening). Outside the city you'll find good and cheap highways and not much traffic. Outside Lisbon is also easier to find authentic portuguese food and handicrafts.
If you want to hear some fado music ask at your hotel reception desk. I suggest A Severa, a Fado place where you can also have a dinner (not to cheap, actually).
Do you want to eat good fish and seafood? Search for the restaurants with an aquarium at their window. You should run away from restaurant where the seafood at the window is not alive. I suggest to lok for a restaurant at the Baixa area (the streets between Rossio and Comercio Squares) or near Cais do Sodr��, the port and fishmarket area. You can search also at Rua dos Bacalhoeiros (Cod fisher's Street), near Comercio Square. if you want to taste real portuguese food, not too elaborated and not too expensive, search for Estrela da S�� (Cathedral's Star) Restaurant, just a few yards from the cathedral main entrance and San Antonio church. It is a traditional tavern where a lot of portuguese people used to eat. It is becoming a tourist attraction, but it still is cheaper than the average and it serves authentic food. If you want to try fish dishes, I suggest Carapauzinhos con molho de pao (small mackerels in bread sauce), sardinhas (sardines) or bacalhau (cod). other common fishes are engu��as (eels) and tamboril (anglefish). Fish rices are quite common. If you find it, try Arroz de tamboril e camarao (rice with anglefish and shrimps) or arroz de polvo (octopuss rice).
If you are looking for something more expensive, book a table at Fartabrutos or, if you are looking for the most exclusive places in town ask for Gambrinus or for the restaurant at Hotel da Lapa. If you have a sunny day, I suggest to eat at the terrace of one of the restaurants inside Castelo de Sao Jorge (S. Jorge Castle). The are not the cheaper places in town, but the serve good food and they have the best view over the city. Go there, even if you just want to drink a coffee.
About weather, Lisbon is not a cold area. you can expect an average 16-18 C degrees (I think its equivalence is 60-64 Fahrenheit) and it is not a rainy area. You shouldn't expect high temperatures nor real cold. Nights are cool in november, but during the day you'll find a great temperature to walk around.
Well, I hope these suggestions may help you. Anyway, if you want to know something else, just write a reply.
Greetings from NW Spain