My mom's new boyfriend?

At the age that you are there is really not that much that you can do. I think if you have tried talking to her and she still hasn't changed it will be hard. If I was in the situation (which It's kinda similar to mine but not a lot) I would locate a family counselor. I had to finally open up to someone I trusted at school to guide, I talked one of my close teachers. She helped and aid me to getting a family counselor. I still had problems a little after wards. I then moved away from my mom. I had to show her that I wasn't happy at all and that I wanted to get emancipated. I always had thoughts of running away but I loved my mom to much to do that. I moved with my aunt for a while. My mom then started to miss me and realize what she had done wrong. If you have a adult that you trust to help you then confide into that person. Seek a happy place that you and your sister can go to to live for a while. Contact you father and reach out to him for help. No matter how much you might dislike or not feel comfy. But maybe he can do something to help.