Help for Camila

About a month ago, we rescued a sweet 6 year old cat, named Camila, from the Coulee Region Humane Society. At her initial vet appointment it was discovered that she has a severe infection in her mouth that will require surgery and treatment. All together, this will cost $400. I've called around to area vet clinics and those that allow payment plans aren't accepting new patients and all the others require payment up front. I want to get her the help she needs, but being a single parent of three kids, I just can't afford to pay $400 up front. Please help Camila to be relieved from the pain she is in. Thank you.