my Georgia will potty on the pad but then run into the other room when I'm not looking and poop in there....
but sometimes she is just fine and will eliminate on the pad. My dogs aren't let outside because the park I live in, doesn't know I have dogs. it's a freaking $300 non refundable per dog, plus $10 extra per dog on every month's rent. Not only that, but we can't leave them unattended outside and if they aren't on a leash outside we have to have a chain link fence up. So, more or less, I sneak them to the park via car, or sometimes they come outside with me in the back for a few minutes... I'm sneaky
but I digress....
Yorkies are tough to train but it sounds like your baby is doing great!