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I'm sorry to hear about your situation. She would need to be evicted. As a resident of the property, she has the same rights as a month-to-month tenant would have. That's 30 days written notice to vacate, either given to her or placed on her door (if she's in a different room). Basically this form needs to say "You are hereby given notice that you need to vacate the premises within 30 days of this notice. If you do not, a forcible detainer (eviction) action will be filed against you."
After the 30 days are up and she still has not left, you can file for an eviction in the justice of the peace courts in your county. You would need to contact the justice of the peace courts to find out the specifics in your county. They'll typically have the forms and tell you what you need to do (you'll need to give notice to her through service of process through a sheriff, constable, or process server, which they can set up, as well as have a hearing). After the hearing, the judge will sign an order of eviction. If she still doesn't leave after a few days, you can apply for a "writ of eviction" and have the sheriff forcibly remove her from the premises. Again, the justice of the peace court in your county will have this information about what specifically is required in your county.
Hope that clears things up a bit. If you have any other questions, please let me know. If not, and you have not yet, please rate my answer AND press the "submit" button, if applicable. Please note that I don't get any credit for the time and effort that I spent on this answer unless and until you rate it positively (3 or more stars). Thank you, ***** ***** luck to you!