Placing A Lien On House

I bought a house with a shared driveway. I own the driveway. In the deed there is written agreement stating that the neighbor is responsible for 50% upkeep on the driveway. I had the driveway resurfaced this summer and the neighbor does not have the money to pay her half. She says she will pay me when she sells her house. I would like to place a lien on her property to assure I will get paid. What is the best way to do this?

Thank you
Scott