Want us to come to your store and take care of her? 
I'd follow everyone else's advice and talk to your boss/supervisor. There's no way this woman should be getting away with what she's doing. Have you talked to your co-workers about it, or have they mentioned it? They shouldn't be standing around and just watching this happen.
If you run into this lady outside of work, try to keep calm, but remember it's not a work situation so you can maybe say a few of the things that are on your mind
Wouldn't go too far, but maybe just tell her to back off and get a life.
Good luck, keep us posted!
I'd follow everyone else's advice and talk to your boss/supervisor. There's no way this woman should be getting away with what she's doing. Have you talked to your co-workers about it, or have they mentioned it? They shouldn't be standing around and just watching this happen.
If you run into this lady outside of work, try to keep calm, but remember it's not a work situation so you can maybe say a few of the things that are on your mind
Good luck, keep us posted!