F1 visa renewal or new F1 visa

[sunilreddy]

Hi.......I came to US during Aug, 2010 for M.S in Chemistry. My visa expires on Aug 31, 2012. I'm planning to visit India during May 2012, get back to US and finish my graduation. I'm admitted into the Ph.D program which begins from Aug 21, 2012 at the same university. So, I'm planning to apply for a new F1 visa when I visit India based on my new I20 (for Ph.D program) as my current visa expires by Aug, 2012. Can anybody suggest if this is the right time to get a new F1 visa? Also if I did not get a new visa can I still be able to get back to US with my old F1 visa . I would also like to know if they reject the new F1 visa application do they also reject my old F1 visa?

Can anyone help me ASAP!


Thanks a lot!