You describe a very difficult situation. It is understandable that you are feeling torn.
You need to learn how to have a relationship with your mother with boundaries. It is not all or nothing.
I don't know what to do for the best really. My mother was only 14 when Iwas born so I understand things were hard for her, but I can't afford forher to takeover mylife. My husband is worried she'll want me to be her slavewhen she gets out.