We were in San Antonio in March and I visited two very nice shops.
The first was "Seventh Heaven" which is in a strip mall on the north side of town inside the beltway and has a great selection of books, patterns, fabric and wools. Very friendly, I really enjoyed looking through all the goodies. The other was "Las Colchas" which is a very cute shop close to downtown located in an old home. It was also very friendly and had also had a great selection of wools and fabric and unusual quilting items. I would recommend both shops - their links are below.
http://www.seventhheavenquiltshop.com/
http://www.lascolchas.com/
Have a great time this weekend!