Peanut's ACL Surgery

Peanut ruptured her anterior cruciate ligament.  What does this mean exactly?  It means her right hind leg is more or less dangling off of her and she can't use it until she gets some surgery.  She hobbles around on three legs and is currently on anti-inflamitories and painkillers.  She needs an operation, it's gonna cost a bundle and we are strangers in a strange land having just moved to Austin, Texas.  We feel a little lost, and now this.  The surgery is roughly $3000 and she is scheduled for an appointment on January 8, at the Central Texas Veterinary Specialty Hospital.