If you really love the place then why not simply close escrow and then evict the seller. The eviction process is not a walk in the park but this person may take your blood money and still not move out.

Has the seller signed the grant deed yet? You may want to check with escrow if everything has been signed so that escrow can close in a timely manner regardless of what the seller is doing to try to extract the blood money from you. If you find that escrow can close regardless of her demands then I would simply close escrow and evict.

The problem with playing along with her demands is that you pay without proof of her going. I guess if you can arrange it that she is vacated and then give her a check then it works out okay for you.