Puppy needs vet

I adopted a puppy from the shelter about a week ago his name is loki. Sadly Loki has just started showing signs that he has parvo. He has been vomiting is running a fever is will not eat and has no energy. Loki would have contracted it while he was living in the shelter but did not begin showing signs till now. The shelter will not do anything since we signed a contract saying he may be sick and that we are responsible. He needs a vet immediately or he may die. I sadly can not afford this at all right now and it’s very sad because we have all became so attached to this puppy already and losing him would break our hearts. Anything will help if you can.