Hi,
My wife amd my kid came to USA on Feb 2007.she has never left the U.S. ever since. Is she a resident alien ?

If you are resident, then you can file joint return as residents even if your spouse has never been to the U.S.
Yes, your spouse and kid are residents for 2007. File joint return and claim your kid as dependent. Attach W7 (ITIN application) with your tax return.