Tabitha, kind of having trouble understanding. Did the mother nurse the puppies for about a week before she ran off? If that is the case, and she was vaccinated, it will not do any good to vaccinate the puppy now as his immune system would not build any antibodies to the parvo.
You could take the pup to your vet and have blood drawn and submitted for antibody levels. If you cannot afford this, the soonest you could give the vaccine is 6 wks. It would be a waste to give it any sooner.