My advice is to stay over in BA for a night or two. Great restaurants. Try the strip in the Puerto Madero section of BA for fancy food, or, if you've got great cajones, there's a really terrific mom and pop restaurant on a corner, right across from La Bombonera, the stadium where the Boca Juniors play. Not a great neighborhood, but OK if you take a taxi.
There's also a couple of Irish Pubs downtown, and the city is quite magnificent.