If you demand the whole thing or even part of it the chances of you getting anything back is almost 0.
Best thing you can do is ask her to pay back 5 dollars a month, at least you will have something.
Or if it's 2000 she owes ask her to settle it for $125 bucks
The key here is to get something back without complicating your life.
Learn from this, never borrow money you are not ready to lose.