How Do I Break A Lease?

My roommate and I have not exchanged deposit nor keys with the landlord, and we notified him ~1 month in advance that we would not be able to meet the leasing agreement as she has taken a job in another city. He is still requiring us to pay rent, or to put an add in the paper to sublet. We have no keys, so we can't show the property by ourselves, and our landlord is not timely in coming to the showings. What can we do to escape this situation?