I know you don't want to give Molly back, but it is the right thing to do. I, for one am pissed that somebody would put a yorkie on a car.
I personally don't understand (and I know people handle loss differently) trying to get a new puppy within that time frame.
*Take the money, start saving for your own yorkie. I also agree with others about looking into a rescue yorkie.
I thank you for taking such good care of this girl and would pray somebody would care so well for mine.