I know there are a lot of posts on foreign exchange already - have gone thru them but haven't got the answer yet. We'll be coming in from Vienna and reaching prague train station at 7.30pm. We will be carrying some euros and USD with us for earlier section of the travel. How do we have the same exchanged to take the metro to the hotel (will get more later at exchange.cz as recommended). Lil worried of being stuck with no currency if the ATM card doesn't work. Should I exchange currency before leaving from India/can I get it in Vienna/Prague?