I wish I could escort you personally, but I'll just have to pass along this recommendation: Bohanan's Bar, on Houston Street. Classy, old-school bar, classic cocktails, impeccable service.
Their website seems to be down, so here are some reviews from Urbanspoon:
http://www.urbanspoon.com/r/39/14993...ar-San-Antonio
I'd also recommend happy hour at Luke, in downtown. It's every day from 3-6pm. You must try their version of a French 75.
http://www.lukesanantonio.com/
If you can, try The Monterey, a funky gastropub that's actually worthy of the name.
http://themontereysa.com
And of course, the best margarita in town, at El Colegio bar at La Mansion del Rio hotel downtown. Even the house margarita is made with Herradura.
http://www.omnihotels.com/FindAHotel...ionDelRio.aspx
Enjoy our city!