Definitely try Austin Pets Alive! (they can probably take him/her? in as an 'owner surrender' and take care of him and then you can have the option of adopting out when they're healthy again, or they can probably do the surgery there, Dr. Jefferson is the kindest person I have ever met!--for little to almost nothing. Talk to them, they will probably try and turn you away but just keep talking to them. Try the medical building, Building C, I think. The one furthest to the right when facing the buildings) I used to work there (TMI for this site?, FFS, I don't really care when it comes to saving a kitty's life!)
Emancipet, or Animal Trustees of Austin can probably help, too, if for some reason APA just cannot or will not help.
If you need to, I can give you a few email addresses you can try for APA if you promise not to say who sent ya. (I didn't exactly leave on good terms...)
Hugs and kisses for your pets!
Here are a few of my kitten! To try and cheer you up :3