Yes I agree that you should discuss your options with your vet first. Maybe her aggressive behavior is because she is in pain, and if the vet thinks with pain medication she could live a fairly good life then I don't think she needs to be put to sleep.
Everyone has different feelings about putting an animal to sleep, and personally I would only do so if there was no way that the animal could recover or live a fairly good life without too much pain. I'm sorry about your dog . I hope that you can figure something out and that she does ok.