I don't believe you want to wreck your Mothers house just because of your subjective hate towards your step dad..
Dont wreck your Moms married life. Separation will be traumatic for her, don't gift her that.
Your step dad has in clear terms told that he had taken more than he could chew, so don't be shameless and still carry on being a burden for him.
I would suggest you alone should move out on good terms with your step dad and live like hundreds of youngsters living independently in the city, it wont be a big deal.
Later you can see how things pan out and may be your brother(s) can join you if they too have tough time handling your step dad.
Leave your Mom and sisters in that house, let them live like a family till the time it is manageable. Dont pollute their minds, let your mom give this relationship enough time.
G_One got a reaction from OLee in My stepdad hit me.