I just joined Yorkie Talk too, but I have learned from pup, that sometimes it works to tie a bell to the "potty exit," and train them to ring the bell when they need to go. Right before you take the puppy out to potty say "potty," and ring the bell, then see if your puppy will ring it. Eventually, your puppy will hopefully ring the bell when he needs to go out. I also leave newspaper by that door in case we can't get out in time. Even when I am gone, he goes on that newspaper 80% of the time and I leave him out with my other dog all day ( of course you must be cautious with this until you know how your pup will react!). Good luck! This may not work, but it did for me, and it took about 1 month to get my pup fairly housebroken.
Best wishes!