Your new puppy will be a baby for at least a year or longer, and house training is a necessary teaching curve.
Do not expect it to be fully house trained before that time, although sometimes your Yorkie might be trained sooner. If it is, then you're lucky.
Just like a child, house training is a gradual process, it won't happen overnight. Just because you had one or two accident free days, does not mean they can be trusted and just because they are trained in one room of the house does not mean they are trained in another room.
Every room is a new world to them. As you allow them more and more freedom, you might have to retrain in every room. Though as they come to learn your commands it will get easier and they will catch on quicker.
There are many different methods, such as can be found on the Internet. The method you choose is up to you, but whichever one you choose, be consistent. If after a week or two, you have not made any progress, than perhaps you should try another method.
Remember if the house training is not working, it is because you have failed to communicate what you want, to your puppy. It is not that your puppy is being stubborn. They really do want to please you; there is just a communication barrier.