Alcoholic Mother Who Is Always On The Computer & Angry Father Who Is Never There

Hello. I'm a15 years old-girl who is having severe problems at home. I'm embarassed of my parents behavior. My mother is acoholic, and she is addicted to `world of warcraft' . It hurts my feelings to see her like that, because we used to do everything together. From A to Z. -But now, it's different since 3 years. She is out of control, and i can't do anything to help her. My dad has already given up on her, and he is never there.
All i was asking for was to have a good mother-daughter relationship, because i'm crossing a step in my life that's complicated, and so i need someone to talk to. My father is always out playing golf and tennis with his friends, and he always gets angry at me for no reason. I don't feel in security being with him, because he is very violent, and he hits me sometimes. I wish i could run away from home. It's so difficult. I have already tried to write a letter to my parents, but it ended up in the garbage. Anytime i try to talk to them, my mom finishes by crying and locking herself in her room. Then, my dad yells at me for hurting my mom's feeling.
Is it a desperate case? Or is there still hope to find the loving family i once had before?
Thanks in advance.