Need to Owner Occupy: Tenant didn't sign original lease

[Naftali Tolibas]

Just closed on my first property (duplex) and I need help!

Long story short: The tenant does not have a signed lease (Owners may have forged, and I did not do proper due diligence) and I need to have her out. We've agreed to 60 days, however the written letter I've given her was to terminate her month to month lease, which is invalid because her signature isn't on it. What would you do? 

On top of that, I originally went to give a formal letter stating change of ownership, and to collect rent. I didn't bring up the rent collection because she was very angry and emotional. She had lived there for 18+ years, and it was overwhelming for her. How should I approach this situation? Please help a brotha out. Thanks!