We have fulfilled our 12 mo. lease and plan to move 6 mos from now. The landlord refuses to honor a 6 m lease?

Instead we have to sign 12 mos, and sublet. We'd be responsible for the collection of rent, the condition of the property, etc. And our security deposit wouldn't be refunded until the 12 mos had ped. We're moving 7 hours away, so policing the tenants and property is impossible. We've been good tenants, paying on time, no demands, no complaints. How can we get out of here next May 30 without so much hle, and with our money? We're retired and every penny counts.