Welcome and Congrats on your new baby!
I'm sure your vet will be able to tell you more about her teeth/breath- I will hope that a good cleaning and good diet will be all she needs. You might browse the diet/heath section for information about high quality diets and different products/methods for keeping teeth healthy- and helping with her breath. I am considering changing to a raw diet cause I hear it helps with their health overall and is good for their teeth and breath.
I'm so glad she is with you in a good loving home. I can tell you will be a great yorkie mom- cause you are already on here educating yourself
Can't wait to see some pictures of your new furbaby!