Keep track of all your expenses in this regard, and submit a bill to her for these costs that were precipitated by her action. Be sensible about it (don’t come up with some rent figure for your in-laws as they were doing what any family member should do).

Let her know that you will be seeking relief in small claims court if she doesn’t cover your costs. Be open to accepting a reasonable counteroffer from her to not have to mess with the court action.

Also check out your state laws in this regard. It may be there are some basic statuatory damages you can claim in a case like this.