I'm surprised the breeder is asking you to offer them money. Most good breeders would take the dog back and find them a new home themselves. By that I mean directly through the breeder, not sending you to the original owners house. Good breeders usually have you sign a contract saying that if you can't keep the dog to return it to them and no one else.

You are not BUYING this dog, you are resucing it. Dogs are not investments, so she shouldn't expect to make up for lost money. She should just be thankful that you are happy to bring him home with you and give him the great home that he deserves.