I would call legal aid and pose this question. Too many people are taken advantage by landlords in this city because they do not know their rights. I am curious if this is an independent landlord who owns less than three properties or perhaps a complex? Different laws apply in these circumstances. In general, information of rental increases will be in the lease if it was not then that could be in your favor. Also your roommate moving out should not affect your issue because you will remain in the unit and still hold tenant rights; this is the same as when you signed your lease or even if you were squatting in the unit. Last question is whether or not your original lease stated that following the fulfillment of your lease then month to month would apply? If so then I personally would refuse to sign another lease. The contract said month to month and you hold all the rights. Oh tricky landlords!!!