Hi Si
We stayed at the Hotel Marketa a couple of weeks ago for the Tomicek Memorial meeting. As others have mentioned this is a fair way out of town, although it is convenient for the speedway and it was so close we could hear the bikes from the hotel.
The hotel itself is very nice, clean, the staff spoke good English and gave us a good discount for paying by cash. If you were interested in staying there, their website is: www.europehotels.cz and their telephone number is: +420 220 518 316-9. The centre is accessible by public transport or a taxi which cost us 300 Kr. We had a hire car but off-road parking was limited. There is also a supermarket and a couple of places to eat close to the hotel (the hotel itself doesn't have a restaurant). Hope that helps and enjoy your trip to Prague.
Chris (another Racers fan in mourning)