H1B exten denied cn I gt on F1 visa is valid til Jun 2013?

Hi,

I came to US on student visa with validity from 20 June 2008 to 19 June 2013. I got approved H1B from 1 October 2011 and expired on 30 September 2012. I filed for H1B extension and received H1B extension denial only on 2 Feb 2012.

Since my student visa has validity till Jun 2013 can I take admission in masters program, get new I-20, go to Mexico and get my I-20 stamped when entering back to USA so that I can get on F1 status again?

I think you need both new I-20 stamped and a new F-1 visa stamp in order to return on F-1 status. Besides you need to leave US ASAP as you start accumulating illegal status once your H-1 extension has been denied and I-94 is already expired.