Another thing I learned working in US is always to try to interpret other's intention in a positive way, especially at home. Your mother-in-law may have lots of issues, but she is still your family and she is here to help you. If you can think positively and be more forgiving and be more appreciative of her help, it'll make your life easier.
There are ways to make your relationship better with her, like buying small gifts once in a while, flowers, fashion jewelry and even clothes. I used to do that for my mother-in-law and it worked great. I think my mother-in-law liked me more than her son. At least when I go back to China to visit my in-laws, their entire family are very nice to me.