I HAve Durable POA for my Mother but it's in my maiden name, which is no longer my last name.

Your power of attorney is still valid although your name has changed. However, the purpose of having a power of attorney is to use it as proof that you have the authority to act on behalf of another person, so if a third party saw your document, he or she may wonder if in fact you are the same person as the name on the document. Therefore, I recommend having the durable power of attorney updated with your current name. I would also suggest considering a medical power of attorney for your mother because as she gets older, there is a possibility that she may not be able to make decisions for herself. This will also allow you to find out what her wishes are concerning life sustaining treatments and other medical decisions that may need to be made in the future.