I agree with those who've said to document it. Don't be afraid to take this to small claims. That would definitely get the woman's attention.
Furthermore, do get a squirt gun and fill it with either the vinegar/water mix recommended above or lemon juice/water. Don't be afraid to spray it in the cat's face--the acid will sting their eyes without harming them. It's a training tool often used to get cats to quit scratching.
Also go to your local pet store and inquire about cat repellent. For instance:
http://www.petco.com/Shop/Product.as...3d23%252520140
Also, cats HATE sticky things--so if you could make the approach to where this cat is scratching sticky somehow, it would probably help keep the cat away. I find double-sided tape works well.