Don't know if this is possible but maybe your vet could call another vet in the area and see if she could ask them to fill the prescription or just prescribe Rimadyl instead of the generic for now.
I looked online and saw the price at about $70 for 60 count 100mg Carprofen or Rimadyl 60 count 100mg for $100. That was at 1-800-Petmeds which are legit. BUT as you say, you need them now. However, it may be worth noting for the future. Always look for the VetVipps seal (usually at the bottom of the page) as it shows they are certified.
Novox for Dogs - Rimadyl Generic Pain Medicine (NSAID) - 1800PetMeds
Rimadyl | Arthritis Treatment for Dogs - 1800PetMeds