SK, my background is similar to yours. Both of my parents are alcoholics, and have been as long as I can remember. I have a half sister, but she moved out when I was 8, and we have very little contact. I went to a local commuter college, but chose to get my own apartment (with roommates), to have some sanity. I paid for it with small student loans and a part-time job. I graduated with a high GPA, even though I held down a p/t job during school. (Frankly, it helped build my resume.) Working while in school wasn't ideal, but I decided I could spend my time dealing with the craziness, or I could spend my time at a job. The job was less stressful, by far. My parents paid for my schooling, but I paid for my living expenses. It was a compromise I could live with.
If you do want to move out, talk to your school's financial aid department. If your father is still willing to pay for school expenses, you may be able to get an apartment (or live in student housing), and pay for that part yourself. (In my state, to be considered for aid on your own, without considering parents' income, you'd have to be declared emancipated. I don't know how it would work in your state.)
No, you are not responsible for her alcoholism. Like nodaybut2day said, you're trying to fill a hole that can't be filled. Shifting the blame of her alcoholism to you is classic alkie talk. They really have no concept of reality, and will say what they have to say to justify their continued disordered behavior. (Believe me, I have heard some doozies!)