How do I tell my husband's family that I am done being the caregiver?

I realized that I started asking this question in another post and it probably wasn't the right place, so lets try here.
My MIL has lived with me for the past 11 months. When she moved in, the doctors told us she had about 2-4 months left. End stage cancer (pancreatic, liver, spleen). She has always been a pretty nasty person, that girl in high school that was your best friend to your face and then the moment your back was turned said the most terrible things about you and spread nasty rumors - yeah, that is my MIL. She has spent her life as a martyr, using people's sympathies to her advantage and to get people to do things for her. She is a pretty negative person, and never has been able to empathize for other people's situations. She turns everything around to always be about her, and always has to "outdo" everyone with her problems being worse than theirs. But she is my husband's mother, my kids grandmother, so I have looked beyond her behavior and loved her as I love my own mother.
When she got sick, I of course stepped up and did everything I could to help her. Surgery and Chemo were not successful, so when we found out in June that the cancer had spread, we moved her into our house and decided to make what time she had left filled with laughter and surrounded by family. That was 11 months ago, and now her personality has taken its toll on my kids and myself to the point were no one can stand to be around her. My husband and his brothers help me, they each spend a day with her so I can work but only having to spend 6 hours with her a day makes them less annoyed with her nastiness than myself - I deal with it ALL THE TIME!
Things have become pretty heated the past couple months, especially bad this past month. She fell and was "out of it" for a few days, turns out she was not taking one of her medications (she was dumping it because she doesn't like the taste), which is what cause the temporary dementia. Once she started feeling better and coming around, she accused me of over medicating her and said that was the reason why she was getting "loopy", so now she documents in a log every time I give her medication, the name, the dose, the time. I am the only reason she is still alive, I have fed her, stayed up all night with her, bathed her, taken care of her when no one else would. I have given up my life for her for almost a year. I caught her last month on the phone with a cousin saying that "Well, you know...she just does the best she can" in a rude tone. I couldn't believe it. When I confronted her about it, she said I was too sensitive and that she meant that I do a good enough job considering that I also have to take care of my kids and can't focus all my care on her. She has also told other family members that I am not attentive enough, one day she had to wait 20 minutes for me to bring her tea. She says nasty, snide comments all day long and I am just fed up. I have spoken to my husband, told him I don't deserve to be treated that way in my house, to which is response is "she has always been that way". Well, she may have always been this way, but I don't have to put up with it anymore. If she cannot find a way to appreciate what I do and have done for her, then I can't and won't do anymore.
So how do I tell my husband's family that I am done being her caregiver and that I do not want her living in my house anymore? I have had some health issues lately due to stress and anxiety, my kids hate being home and I have no social life anymore. I can't keep doing this. I have no idea how much longer she has left - it could be two weeks (which I can handle) or it could be another 6 months (which I cannot handle).
Thanks for any advise.