@Kyle H. has many STR's there and can tell you more of the harsh realities.

Keep the house well maintained and clean so I hate to get rid of them but the drama is starting to get old. 

Unfortunately some of my responses on here can be a bit harsh depending on the day I've had lol. 

For an extension like this you could just let the lease go month to month if there is a provision for that and don't worry about the deposit until she moves, this moves the drama to after she is out of the property.   

You do not owe your tenant help in reducing their cost to break the lease, especially if the cost is you ending up with a new tenant who needed to move asap due to poor planning, being behind in rent, or drama.

@Harsh Thakker, thanks for your insight. can you give me an idea of a site that you looked at, in which the number didn't work out?

After several years of student housing drama/damages Burger King bought it & the one on the corner for 3x their initial investment. 

If you are relying on current rentsI’ve seen Zillow listings in Cleveland with existing tenants at $500 and $600 “that really wanted to stay”.I assumed it’s because they have been there for years, they’ve been reliable, the seller was happy with what they got, and/or the house was inherited.If they bought the house +15 years ago at $40k, $900/month of drama free gross income was probably nice.I didn’t want to buy it as the neighborhood was not that great and the ROI to get it at $1.2k of rent wasn’t worth it.

I will say that the more people that live in a single house the more drama you will have. 

Less turnovers, drama and better returns.