I recommend two places where you can stay, they are close to the center .. I do not know what your budget is but not too expensive: the pensión kursaal and the pensión aida, you can sleep there for 30 to 150€ the night, both of them have near by a bus station. Regarding the transportation you can check out this
site. I recommend you to buy the TouristCard i think it's 12 journeys for 16€ o 6 for 9€. I hoped I've help a little! Enjoy your trip, it's a wonderful city.