I moved into an apartment on June 6, 2012 and signed a one year lease. I am disabled and can no longer maneuver the stairs to get up to my apartment. In looking over my lease, the end date of the lease is stated to be May 2012. It's obviously an error on the landlord's part but per the lease, the end date of the contract has passed. I've found another place to rent without stairs and would like to be able to take it. What are my chances of getting out of the lease?

You're not going to be able to get out of the lease based on the typo. Your best bet is to speak to the landlord about your situation. They may let you out of the lease if they have someone else to rent the apartment. Or they may let you out in return for a payment, such as forfeiting your deposit. They may allow you to find someone to take over the balance of your lease. But you'll have to speak to them about it.