If you had a lease at a certain amount of money and went on to a month-to-month basis, you might check with your attorney, but I believe the lease terms stay in effect.
I don't know how long you intend to stay, but even if she tried legally to have you removed (and you are paying her the rent), it would take a very long time to get you out (and possibly costly for her).
Morally, you can call LIBOR at 631-661-4800 and file a complaint (called a grievance). They will give you the instructions. You also have the Dept of State to fall back on.
Personally, I would want to know who she is. As a broker, I prefer not to do business with unscrupulous agents.
To tackle the ethics concern, I would contact the agents broker/manager and follow up with a complaint/grievance as Gail has suggested.
You will need a real estate attorney for your purchase, he/she can advise you on your rights as a tenant and whether you are being wronged. Here in NJ the laws favor tenants rights. There is information - much of it summarized in a government publication which we require be given to both tenants and landlords that we assist. You can also consult the HUD website: http://portal.hud.gov/portal/page/portal/HUD/states/new_york
Good luck to you,
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Your case is an illustration of why real estate agreements must be in writing.