Ten, according to yellowpages.com
I know they sell it in 24oz bottles around the Dallas area at corner stores, and have heard that Handy Andy in San Antonio sells them
San Antonio has quite a number of places for Automobile Storage - try Attic Space Laredo, Mackey's Boat & Auto Storage, Public Storage (Center Park Boulevard) or Uncle Bob's Self-Storage.
It is 347 miles according to Google Maps.
It is 4.75 hours according to Google Maps.
It is 246 miles and an estimated driiving time of 4 hours and 26 mnutes accordng to Google Maps.