H1B Visa renewal help

[srijanga]

Hi
i have H1b visa stamp till 27th jan 2013
my I797 expires on 31st Oct 2013

if i go for visa renewal in seprtember or october will i get visa till OCT 2013?
can i go to mexico or canada for renewal?
if i get stuck in mexico or canada will i be able to enter US since my status has not expired yet?

can someone please help me

[alliesv]

Your H1-B expiry date will be written on new I-94 card; when you entered the US last time. It will be in your passport. Visa expiration date isn't same as your H1-b expiration date .