It's not that simple. She has been around a long time and even though she isn't a manager, seniority goes a long way at my company. My manager has mentioned it to her, but realistically that's as far as he can take it.

Ask for a place farther from her, perhaps switching with some other talkative colleague in a better spot. If manager rises eyebrows, argue that she is too loud and inconsiderate(unscrupulous) to other people. Even better if more colleagues share this view, make a move together.