Can you explain your situation a little more please?
Your options are: go to court and get an order from the court for her to implement the agreement within a given period, or, go to court and ask the court to make an order to sell the house. That usually focuses minds on the issue. In both cases you would seek the expenses of the action from her. Happy to discuss further. I hope that helps. Please leave a positive rating so that I am credited for my time.