Your dog is truly suffering and you need to get help from a vet. Try calling various rescue groups or see if a vet will help you finance the cost or allow you to make payments. Even the local animal shelter or ASPCA may be able to help you. If she has pus in the wound it is infected. She needs professional help now. This is probably not what you wanted to hear but you need to do this to get your dog better. She is in pain and needs treatment.