Mother does not want a "helper" and continues to depend on me.

My mother suffers from fibromyalgia, arthritis, debilitating anxiety and panic disorder and is generally unwell. I also suspect her of having a narcissistic borderline personality. If I felt I could, I would cut her off immediately. I have no feelings of compassion towards her. The problem is that I am financially tied to her. She could not get a lease with her credit so I helped (because she threatened to move in with me if I didn't). She's said if I ever stop helping, she will stop paying her rent. She leased a car with my co-signing then could not afford the payments, so told me that I should switch her my paid off car with the leased car. I am driving the newer leased car but she has threatened to come get it and hide it from me, and I'll still be stuck making payments. Anyways-- she does not drive farther than a minute from her house. I drive her everywhere. I have suggested (at the suggestion of this helpful forum!) to get a "helper" for her to drive her places once or twice a week so that I'm not left doing everything. Her response? "I absolutely will not do that. If you have the money to hire a helper, you can just give me that money and continue driving me." WHAT? So frustrating. This morning I took her to surgery and she actually told me "When I am getting a procedure done, I am God." I cannot take this anymore.