Renter wont sign extended or new agreement. What can I do in TN?

We rented a lot to a friend so the mortgage co would make the sale and allow her to put her double wide Mobile home on the lot. We signed a one year lease for $0 amount knowing later we might have to rewrite the agreement. This was a very good friend in desperate need, so we have not asked for her to sign a new agreement for 2 years. This person is well off enough now to easily manage the rent. I have recently lost my job and now WE are desperate. She will not sign the agreement..where do we go from here?