Where abouts in belfast will you be staying?
Some of the newer bars in Belfast have very good food- Irene and Nans, Cafe vaudeville, The apartment for example.
Cayenne on shaftbury square is very good, as is Rin City on the Malone road. Nick's warehouse in the cathedral end of the city is very good too.
If you're really into your food like me, you'd enjoy Deanes restaurant and also Roscoffs...both Michelin star restaurants.