Can't Handle a 3rd

On Saturday afternoon, my dog Diamond attacked a neighbor cat.  In the process of getting them separated, I jammed my fingers in her mouth, which did not stop her biting.  Diamond continued to bite down, forcing her teeth through the nail bed of one my fingers, and broke the bone badly.  My wiggly, lovable three legged dog hurt me... severely.   The bone tip is crushed and I might need to get surgery to repair it.  Turns out, the cat is totally fine, just a few puncture wounds.  All the blood we were afraid of was mine. This is the second time she's jumped on and latched onto a friend's pet, the second time we've desperately tried to pry her jaws apart, the second time a crowd has been drawn by our frantic and incoherent screaming and the second time animals have been whisked away to emergency vets.  I don't think I'll be able to avoid the next time, and what if then it's a child? She strains to get at playgrounds just like she strains to get at squirrels.  I cannot bear the responsibility of that.

Do I return her to Austin Pets Alive?  At least then she'd have a chance of not being euthanized, which would certainly happen if a kid got injured.  But I still love her. She's still my dog. What do I do?

Broken finger