Hi,
My current I-94 expires on 02/18/2012.My current H1b visa expires on 09/01/2012 (my passport expired before the visa and the last time I crossed the border the I94 was issued with an expiration date matching the one of the passport).
My employer requested an extension of status for 3 years starting on 02/18/2012.The extension was approved from 08/31/2012 to 02/18/2015.
The I94 attached to the form I797 states that it is valid from 08/31/2012 to 02/18/2015.

Can I legally stay in the US between now and 08/31/2012? If I leave the country before my current I-94 expires, can I get a new I-94 upon re-entering the US (my visa stamp is still valid - on the old passport - and I have a new passport) or do I need a new visa stamp?
Thanks for any advice.
Marco