What do I do when my mom is verbally abusing me?

My mom is diabetic and comes from a cuban family that treated her badly when she was a child, now she is constantly yelling at my brother and I, telling people lies about us, never lessons to us when we try to tell her she's hurting us, and she wont go to consoling or anger management. she looses she temper to a point where she would brakes thing or threatens her life or ours, and she is starting to act like a teenager when it comes to her cell phone and online dating sites,when we have a problem she wont even care what do I do I can't live like this any more? there are some nice thing though like once in a while she takes us to the movies and gets us thing we like but then later she rubs it in our faces like when we are telling her that we don't like it when she yells at us or bullies us shes uses the fact she get us thing as a way to shut us up, so I don't know what to do.