H1B stamping ( appointment worries !)

[BhatlSingh]

Hi, I am going to India on vacation. My current H1B visa has expired and i have the extension paper ( I797A) with me. I plan to be there in India on 21st Dec and would return on 8th Jan. I would be grateful if someone advise me on the visa renewal process. Can i get an appointment in time to get my passport stamped ? My nearest consulate is at Kolkata.

Thanking you
BhatlSingh