Hi Ravi,
I am in Texas but not in San Antonio. I visited S.A twice. You will have lot of sight seeing in S.A
You are visiting S.A next month i.e July you will see huge crowd there because of summer vacation. Well the famous spot in S.A is water park. You can't cover this park in single day. You will have couple of shows like sea lion show, shamu (whale) shows, 4D-movie (don't miss this one) and number of rides. You have to pay entry fee only and all the shows and rides are covered in that.
Another sights are alamo fort, wax museum, river walk, all these sights are in down town then natural caves and wild ranch.
Don't miss mexican food on river walk.
If you need any other information let me know.
Thanks,
Ravinder Singh