H4B stamping

[Vatsal]

Hello,

Hope all of you doing alright.I'm planning for my wife's h4b stamping.
Here is scenario

Currently I'm in India and coming back to USA in February, 2012. My
current I797 is valid till March 31,2012 and I already got stamped on
that. Also I got my h1b extension approved starting from April 1, 2012
to october 31,2014. Now as I already have h1b stamped till March
31,2012, I'm not going for stamping for my extended I797 at this point
of time.So question is when my wife is going for H4B visa(may be in
february 2/3 week), which EAC no i should enter in DS160? old one
(valid till March 31,2012) or new one (valid from 4/1/2012 to
10/31/2014)? I'm planning to get H4B stamped till 2014 and that is the
only reason I have applied H1B extension a bit in advance and got
approval.

Please advise.

Thanks,
Vatsal.