Hi,
I am a J1 research scholar, came in US from India at the beginning of May 2011. During this period May 3rd 2011 - April 30 2013, I had two contracts (DS -2019), each lasted for ~1yr. For this period I was under tax treaty. I may stay in US for about another one year (till end of Nov. -Dec 2013). So my questions are-

Considering my status as a J1 research scholar in Michigan state:

1. Can I get tax exemption for first 2 years (2011 and 2012) and should I have to pay only for 2013 calendar year?

2. If I have to stay longer than 2 years, how the tax treaty or taxation procedure will work?

Your answers will be very much helpful for tax filing.
Thanks.