2 year old Yorkie with potty training issues

Question
We recently adopted a Yorkie that will be 2 in April.  She is a beautiful dog, but will relieve herself in the house whenever she wants.  We have restricted her to a small area of the house and let her out often.  She is better, but will still go in the house.  I am not sure what else to do.  Can she still be potty trained at this age?  What other tips can you give me?  I am frustrated with her, but do not want to give up yet.  Please help!

Answer
Use a crate-the trick is to keep her in there all day except to go outside,to be fed or when you want to play with her or take her somewhere

Crates are the best way to house train a dog as they will not go where they sleep-and do that for about 3 weeks then slowly let her out more,if she goes back to accident put her back in the crate for another week or so

It's actually easier to house train an adult dog as they can hold it longer