I had filed US tax returns for 2009 and stayed 3 more months (Jan to March) in 2010. Am I eligible for full tax refund considering the fact I have stayed for 3 months in 2010 in US or my previous year stay will have any affect this ?

If I am eligible for full refund, in that case do I need to furnish any form other then W2 , please advise.

You are NOT eligible for a full refund, but you probably WILL get some type of refund back.

How MUCH of a refund depends on your marital status, whether you file as a resident, non-resident or dual-status alien, and other variables.

If you need professional help filing your return, email me at [email protected] or [email protected].

You will pay federal income tax and state income tax as per your tax return.
If you were resident in 2009, you will file dual status tax return for 2010.