Here's a link to the map:
http://www.wmata.com/metrorail/systemmap.cfmIf you click on "trip planner," it will also tell you how to get from point A to point B, and includes links to the bus system as well.
I can tell you that a lot of the Dem staffers on the Hill go to the Hawk N Dove and the Capitol Lounge (both are bar/restaurant combos with reasonable prices), but that is not to say that there are not Repubs there as well. Both are on Pennsylvania Avenue, a couple of blocks from the Capitol South Station (on the Blue line, same as Capitol Heights).
There are also lots of sites to look up bars and restaurants, but I think the Post's is the most helpful:
http://www.washingtonpost.com/wp-dyn/artsandliving/foodanddining/I hope this helps. Where are you coming from?
Good luck!