Myself and two friends needed to move for financial reasons, we found a house that we could all afford. Roommate F. didn't have good credit so to better our changes we agreed that myself and roommate A. would sign the lease. We all agreed to stay the duration of the lease (2 years). During the first year roommates A. and F. had issues and now roommate F. is planing on moving in March, 7 months before the lease is up. We had a verbal agreement, I have in writing were she admits to living there and the electric bill is in her name. If she leaves can we sue, or better yet can we prevent her from breaking our agreement?