I-94 not issued on Latest approved I797A

[jindalfriends]

I travelled to USA from India on H1B on 21st January 2014 and my Visa was stamped till 21st August 2016 and my I-94 was also valid till 21-August-2016. I applied for extension in premium  H1B and it was approved on 11May 2016 till 10 May 2017.

I travelled to Canada by Road for 1 day on tourist Visa on 28th May 2016 and returned back in USA on 29th May 2016. As my stay in Canada was only for 1 day I was issued same I-94 number. As  I was not having my approved petition with me at that time I was given same I-94 number and Admit Until date was also remains same 21-August-2016 which was stamped on my passport.

Now when I was preparing for my Extension I got the below query

1. Is my I797A is still valid or my Canada Visit has made that void.

2. Is it just Issue with I-94 or I797A also has issue.

3 How can I correct it ?

4 Do I need to go out of USA (Mexico or Canada) to get new stamping or I need to my Home Country (India) ?