It is of course entirely your decision but you need to be aware of ALL of the possible outcomes! To get the best quality stud dog you may need to pay the price of one pup to the dogs owners or give them one pup after weaning (thats usually how it works) and if your dog only has one pup then it will end up costing you even more in the long run due to vets fees and other costs involved in raising that pup to weaning and you may end up with no pup (if they want it or the worst happens and you lose it). If something unexpected happens (eg a c-section) then that one pup will end up costing you alot more then the going rate for a yorkie pup especially if its an only pup and you have to give it away or have already paid the stud dog owner! Also a c-section is more likely if theres only 1-2 pups as they grow bigger inside and have more difficulty getting out and yorkies are known to have small litters especially first time round.
The best of luck to you whatever you decide to do
