You are going to need to hire a lawyer to look at this issue. The facts will be very important but every day you delay there is a risk that her claim could get stronger. A delay in enforcing your rights can result in you losing control over property being used by others.
This answer does not create a attorney client relationship and cannot be relied upon as a legal opinion as there are too many unknown facts to this matter to render an opinion at this time. Campbell & Grooms, PLLC http://www.campbellgrooms.com