I am in Texas and my lease was up February 2011 and it was not renewed, I told my landlord in December 2011 that I was looking for a bigger place, how much notice do I have to give before moving out.

Carefully read your lease. Yes, I know it expired but the terms will still control your situation. Look for anything that says how much notice you must give if you don't intend to renew the lease. It may say that you must give 30 or 60 days notice. If so then that is how much notice you need to give.

If the lease doesn't say how much notice you must give them if you don't intend to renew then you need to give them at least 30 days written notice.