Shortsale is absolutely correct.
Everyone should read the Tenants Rights Bill of 2009, brought to you by our favorite President.
Hang in there and Google that.
Make them give you the Cash-for-Keys money too!
Good luck and may God bless
You have rights as a tenant.
"What Are the Tenant Rights and Owner Obligations Under Federal and State Law?
If the tenants residing in the property have leases, they have the right to continue living in the property under the terms of the existing lease until it expires. If there is no lease the new owner of the property must give the tenants at least 90 days written notice to vacate."
There is some good information here: http://www.homehelpnh.org/tenant.htm
Tim is right, you do not a have a lease which is a contract. A tenant at will or month to month means that either party can cancel with notice. Sorry about the bad situation.
Prudential Verani Realty