Lucky, thrown in a well to die needs help!

Her background: Lucky was screaming from a water well in a small city in south Korea.   She was very fortunate that there was a small cave in on the side of the well that allowed for her to crawl into and survive for however long in there.  I heard her sorry screams and yelps and saved her from the well.  She did not want to come out at all and she was grossly underweight and had fleas.  For two weeks I nursed her back to health and saw her grow from a timid pup to such a playful love bug.  But now she has parvo! 

The problem I need help with: she is at the vet noW being treated for parvo. He says she will be there getting treatment for seven days and that it will cost more or less than 500 US dollars.  I need any help I can get! Any money I do not use will go to the vet because he always takes in the many stray cats and dogs in South Korea and helps them.  He told me he has over 40 cats living in his home.  He is so kind and came in to help lucky on his day off.  He runs such a small operation that is just him and his wife.  

Thank you so much everyone!