Welcome to Pet talk. I had a yorkie as a kid. Yorkies are very very difficult to housebreak. Luckily my mom was a stay at home mom so she was able to work with our yorkie around the clock. He was perfectly housebroken, but it took some time and patience.
Now I work at a pet boarding facility and the yorkies that come in (and we get a lot) are hardly ever housebroken. I'd estimate that 50% of yorkies that come in have little to no housebroken skills. Of the other 50% i'd say at least half still have some accidents, and the other half (25% or less of the yorkies I see) are actually housebroke. It's unfortunate as yorkies are wonderful little dogs with this one major down fault.

I'd suggest a couple things. My first suggestion is to clean "the spot" with Nature's Miracle. It's a great product, it can be a bit pricey, but well worth it.
My second suggestion is if you are going to be gone for a long period of time (more than a couple hours) to put a pee pad down for her to use. I have 5 dogs and 2 of them will not hold it for long periods of time so they use the pee pad while I'm out.
My last suggestion is to get help from a trainer. A trainer will teach both you and her a lot of things, much more than just potty training. PetSmart offers an 8 week class for $100 dollars (which works out to only $12.5 per class!) it's well worth it. Hopefully you'll have you're little yorkie for over 15 years like I did. Training will bring you and your puppy closer together and make the years you spend together much more enjoyable.

Good luck and again welcome to Pet Talk!