My girlfriend and I decided to move into a house together that we were going to rent to own. Her credit was not strong enough so the lease ended up in my name. Things got rocky so I decided once the lease was up to opt out of buying it. Since then I've paid the rent up until the day I was staying which was discussed with the landlord, and she told me she was leaving that same weekend. The lease is still in my name and she is still in my house switched all the household bill to her name and refuses to leave and she also paid the rent up until the end of this month. How do I get her out of my house.

Serve her an eviction notice.

We need some details here. When is/was the lease up? When did you notify the landlord that you were vacating and opting out of purchasing?

Why do you say it is "my house" when you cancelled the option to buy, let the lease expire and moved out?