Tenant asking large money.

it is very old matter , we ready to pay tenant but she asking for large money to vecant the room located in our house, we want to sell this property, pls guide 1. how much money reasonable for 12x45ft space. 2. can we offer her same space somewhere else, as we have other property too if "yes" what kind of paper need to prepare. 3. she lived alone there, is it possible that we can do some paper work to avoide in futur claim of her children