Dee--These pups ARE 10 weeks old.
To the OP, not sure what you can
legally do about the deposit without a written agreement, which you
should have had. (Yeah yeah, hindsight 20/20) I would question placing a pup with someone as irresponsible and inconsiderate. I feel like, regardless of the situation, anytime someone makes a deposit and then can't keep their end of the bargain (again, which should be documented in writing) then you are entitled to keep the deposit--that is what a deposit is for, IMO. If you are not comfortable with her having the pup, tell her you've changed your mind and then give her back the money and chaulk it up as the first of many monetary losses in the breeding biz.
Most breeders try to have homes lined up BEFORE having a litter so that they have ample time to screen prospective homes/owners and so they can avoid this problem. Many times when people have problems placing them, they are less strict about who they place them with.
Good luck!