Emotionally bullied by my dad... do I stay or do I go?

Basically, my mum and dad are split and my dad has a girlfriend who lives in my family home. My dad is a sort of split personality character, one day he is the perfect dad! he pays attention to me, cares about my education and my life, and takes me and my sister places and we have a laugh. Other times, however, its not so good. He can get very nasty in terms of words, especially after a glass of vino,which he depends a bit too much on if you ask me. He has been like this many years as my mum went through the same situation. However i have reached a point where i am fed up of going to my room in tears, feeling alone and horrible about myself! I am in a very complicated family situation, we depend on him in terms of money, as my mother is a single parent who depends on the child maintenance as well as her job to feed us as we are with her mostly. And he can get stingy with the money if i am not there with him when i am supposed to be. I am just getting to a point where i'm fed up of him upsetting me, my sister or my mum. And i stood my ground for once last week and walked out, and haven't talked to him since. I just feel like he has such a nasty side to him and it scares me to death, all i want is a happy, normal family who are kind to me and don't feel the need to upset me over nothing! There is a lot more to the situation, i just need to know what is the best thing to do, should i continue seeing him and chance being upset so much, for the sake of being there for my younger sister. Or do i stay at my mums where i feel a lot more comfortable? It is a difficult decision, as he is a difficult man, he doesn't like being wrong or being told what's what so to say! He is a very complicated man himself and has a lot of emotional issues and financial issues which i respect, and i try to support him and do my best with everything but nothing is ever GOOD ENOUGH!!! He has spent years upsetting my mother and i do not want to be his next emotional punching bag any longer. His girlfriend is another matter, she is the opposite of my mum which is difficult, she invaded my family home, and didn't even ask about how we felt about that, and she has her perfect children and always compares me to them. I am fed up of her having such an influence on my dad as i feel she has a lot to do with his decisions concerning us, which she has no right to! She is very pretentious and loves having our nice home whilst my mother struggles to pay for meals! It just really gets to me, i don't know whether to face the music and the awkwardness of being there again after my 'dramatic exit'. It's all such a mess, and i want to concentrate on college, which i can't in this, i will be leaving in under 2 years now and i want this sorted sooner so i can enjoy what time is left with my family. What do i say to my dad to make him listen to me, and make him see he has had an impact on me and that i'm not a 'baby' who needs to 'stop feeling sorry for myself'. He is SO manipulative and makes everyone see his side, and i feel powerless really and so does my mother. My dad really has effected my emotions, i have been so close to self harm before because of it, and i am becoming drowned in it all! I do love him a lot, and i want to make it work and for it to all be okay, which maybe it will never be, but i do not want to grow up resenting him and wishing another man was walking me down the aisle.

If your old enough, GET OUT NOW!!!. I had the same sort of father and he made my life a misery and i stayed at home far too long. It was just as much my fault but i now have irrepairable damage and regret not moving out and managing to salvage some sort of relationship with my father while having my own flat and own life!!. The best advice i can give you, you reminded me of me straight away!!!. HUGS. Good Luck.