ok what do i do??

[Alan Lynch]

Hi everyone i was hoping someone could help me here, i live in Kittitas county of Washington state, my ex girlfriend and i lived in my house amicably for 12 months, she paid/pays me $600 a month for a room and use of the house and she gets free storage which is an outside shop which she also uses to park her broken down van, anyways it has come to the point where i would like my house back and i want her to move out, she has said that she won't move out unless i pay her $2500 moving costs, i don't see why i should do this as i have given her until the end of March 2016 to move out, there has never been anything in writing, no lease agreement or anything, it was just she paid $600 a month plus utilities, she's never missed the rent or anything it has just come time for us to go our seperate ways, but she says she won't move, so what should i do? Any advice would be greatly appreciated