Help Get My Baby Mary Jane Vet Attention She Needs

My Names Sarah and my husband and I have had our baby girl Mary Jane since she was just 4 weeks old. She will be 14yo on November 14th. I never had her spayed because she was never around other dogs. So didnt think it was important boy was I WRONG! Now I'm 95% sure she has pyrometria (Uterus infection) which if isn't diagnosed and treated by surgery is a death sentence. Her stomach is swollen really bad and shes been crying all week (i just thought she was in heat) until last night she cried ALL long and I noticed how swollen her stomach area is. I hate asking for help but Its killing me to see her like this. We have 1 income and my husband doesn't get paid till next week. The vet visit, x Ray's and tests she'll need to have done are around $500 and surgery will be over $1300. Right now I just want to get her seen and tests done. Please help us get her to a vet and checked out. She is like our child and we don't want to lose her. **we have checked with vets and no one will take payments and no rescues can help right now. This is a last resort. **