If you don't mind going over to another neighborhood, yet not that far, Joyti on 18th St. in Adams Morgan is nice and not too pricey. I've eaten there on a number of occassions and have always enjoyed myself and have been pleased with the food. It's Indian so you will find a variety of selections to appeal to your vegetarian tastes.
Also, on the same block are Mezzé and the American Diner. (I may have screwed up those names a bit.) You can get a nice meal in these places too and find a few things that would appeal to vegetarians. You should do well in all three. Just be careful if you are driving because parking in Adams Morgan is impossible on heavy social nights, like weekends.
