New owner tenant lease is up refuses to sign a year lease

[Jorge Guadian]

Purchased a duplex March 3, 2017. One of the tenants lease was up last year so basically they have  been on a month to month. I informed the tenant I was going to raise the rent and if they wanted to continue renting  that I required a 1 year lease. She informed me Mid March she didn't want to sign a year lease. She told me she has been renting there for 2 years already and needs a bigger  place a 3 bedroom instead of the 2 bedroom. She has 2 boys and 1 girl all under 5 years old. Her and her partner (he is not on the lease) have had all of March to look for a place with no luck which I don't think they have really put much effort or they don't qualify. I gave her a written notice on March 31 to vacate the premises by April 30,2017. She  got mad started raising her voice  at me when I gave her the notice she did pay the increase rent for April. She thinks she can stay on a month to month since I told her  March 27 by text I would work with them on giving them more time since they had not found another place at that time. She assumes I said she would stay on a month to month lease. Im giving them 30 more days, I have a text her saying one more month would be great but it just don't sink into her head.   For her working in the medical field she is not the ideal renter  extremely dirty. Dishes piled up, bags of trash or clothes its hard to tell but  clothes  are thrown everywhere, roaches every where. Gnats in the kitchen and bathroom she says the gnats came right after I fixed the leak under the kitchen sink but there in the bathroom also ( what I have investigated being dirty will attract gnats and roaches in a heart beat). Also after I repaired the toilet flapper she said her bath tub became clogged which was false I pulled out a wad of  her hair from the tub drain. I did have a pest control exterminator come to spray both sides of the duplex right after I purchased the place.Her side compared to the neighbors is terrible. There was no roaches or gnats on the tenant side I wish was not leaving due to them buying a home.  Even the pest control tech informed me she is the problem. I love dogs but she has 2 dirty pit bulls living inside doesn't make it better you can smell them and who know what else. The place is not bad for the price I paid  the cash flow is $900 after paying the mortgage. If she was a clean tenant I would not be to concerne about the month to month lease. She is destroying the place is what Im concerned about. I have evicted people before for not paying rent but not for being dirty birds. Technically she doesn't have a contract this is how I figured I could get her out of there by making her sign a new 1 year lease which she doesn't want to ( I'm scared she might since she hasn't found another place). Any suggestions on how to make this a smooth transition. Im in Texas