A very similar thing happened to my husband last year.
The first step is to decide if you love your job enough to want to work for management who would suddenly turn on your after 13 steady years of faultless employment. What does that say about the boss's character?
If you do decide you want to stay, you need to document everything you do. This can take the form of keeping a journal at home in which you write down everything you did that day, and can include photos you take with your camera or cell phone if applicable. Also, document any statements this employee makes to you that constitute threats, or boasting about how she is going to get you fired, etc.
Finally, after you document that for a solid month, make a sit down appointment to talk with your boss. If your boss won't meet, document everything in a detailed letter, and send it to her.
Be prepared to find another job.
My husband loved his job and had worked at the place for 9 1/2 years when a new manager was hired who set about targeting my husband and making it impossible for him to do his job. Even though the manager above this manager knew what was going on, he still chose to continue giving this manager more time, and more chances. Finally, my husband resigned.
Six months later, the manager who had been hired was fired, for theft.
My husband has since moved on to another job.