I had filed US tax returns for 2009 and stayed 3 another 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.

On your income you must pay taxes like US citizens and residents. File Dual status tax return for 2010.