Breaking "lease"

I moved in with a classmate a few months ago. We had an oral agreement that I would move in and what my rent would be. She then called me about a month prior to my move in date, stating she need me to come by and pay first and last months rent. I arrived at the house, and the other tenant moving into the other bedroom was also there. The owner sat us down in the office and gave us amounts we needed to pay. There was a sudden charge for a "deposit" that was I was never informed about and she also made me sign a paper she calls the lease which I was never told that I would have to sign. I've been told its not legally binding since I signed it under duress. I don't even know if it would be considered legal since she just wrote it herself. I now want to move out because she is impossible to live with and lies constantly. Do I have a right to break this so-called lease that I was never told I would be signing until it was handed to me with a pen?

Yes you can argue that that was not what you originally agreed and decline to go forward. But make that known quickly or it may become binding.

Well I am already living with her, so what would I need to do to make that lease so that it is basically void?

You cannot live there and still argue that there is no agreement. So you need to get out and/or give notice that you don't view the agreement as binding.