Orphaned puppy

Question
I recently discovered 8 orphaned puppies at a neighbors who had moved away. The mother had been taken. I took one home and called animal control on the rest. they picked them up 2 hours later-3 had died. Mine is a little girl. she looks like a pit or some medium size of a dog. She whines constantly and nibbles on everything. I am not sure how old she is. She is about 3/4 the size of a gallon milk jug and wieghs 3-5 pounds ( i have an infant baby wiegher. I tried giving her dry puppy food but she only ate 2 pieces then threw them up. I tried soaking them is water-same result. another friend of mine said to soak it in milk. i did the same but she only licked at it a little. I am worried becuase she wont drink water either. Walmart and petsmart have puppy bottles and puppy formula in a can. Can i feed her this? and how can i tell how old she is? plz answer soon. She only sleeps and her poop is slightly runny. OH and sorry for so many questions, but how do i check for worms?

Answer
This is a difficult project I lack experience in.  Check some of the books in your local library.  You are also going to need help from a vet sooner or later.  

Cow's milk isn't good for puppies.  You could try a low salt chicken or beef brought.  Look at the puppy's teeth.  If they are still tightly spaced, it could be a month old or less.  In that case, you may have to go with the bottles and formula.  

Don't worry about worms for now unless you are seeing eggs or segments in her stools.  People I respect say the over the counter worm medicine isn't safe for puppies.  I wouldn't risk it on a puppy of unknown age.  One you figure she is 6 weeks or older, have a vet examine her and give her a combo shot and worm medicine.  Even with the beset of care, puppies often need a deworming.  

Looking back over your question, lethargy and diarrhea are the classic signs of parvo, a deadly disease the puppy's only chance of surviving is prompt, intensive vet care.