Have you looked at the FAQs? You'll find a lot of good info there on attractions, hotels, and restaurants. You should start by reading that and then come back with specific questions.
Philadelphia has great historical sites, which are in the part of Center City known as Old City, or the historic district. There are also hotels, restaurants, and bars in that area, so that may be where you would want to stay. You should definitely stay in Center City (downtown), which is compact and easy to get around.
For more specific hotel advice, you should give us your hotel budget in dollars per night excluding taxes (which add 15.2%) and your exact dates. We don't use pounds. For more specific restaurant suggestions, you should give your budget per person in dollars excluding tax, tip, and alcohol, and tell us what kind of food you like.
What are your plans for the rest of your trip? A car is an expensive burden in Center City, so it may be better to avoid having the car while you're here.
Edited: 6:37 pm, February 20, 2013