landloard question

[Renee Kostermans]

I have been renting my house out to an older couple for 2 years. They moved out June 1st and let their daughter in law take over the lease. she signed a year lease and she told me on June 28th that she had to move July 6th. I was pretty upset and she told me she knew someone who could take over the lease for her. I told her no because I could get at least $400 more per month with a new lease. She was a single mom and I thought we could help each other out. Anyway a few days later A lady calls and tells me that she is my tenants roomate and has been living there for over a month and is getting mail there. She does not want to move and will pay extra per month. I told her no and then she says that she will sue me. This person is not on the lease. What rights does she have? how do I get her out of there? I am in California and the house is in Colorado Springs, Co. I just don't know what to do.