The office you are probably booked for is Via Sardegna; I agree that it can be somehow difficult to navigate there even with printed directions, however it is right next to your hotel. The easiest would be on Viale Europa 351, because it is in EUR (the area that was built for the World Exhibition that never happened because of WWII); it is not very far from the highway and it is next to the subway line B (you will have to make one change to reach your hotel). The area has some modern "sights" that are different of downtown, so you will be able to see those at the same time (including the Church of SS. Pietro e Paolo, at the end of Viale Europa).

http://tuttocitta.libero.it/tcolnew/...=1&pv=1&noc=39