回複：i guess the "H1 visa" you mean here is H1-status.

it will be valid until next April because i797 is the approval notice for h1b status with your I-94. You can get H1 visa stamp from US consult based on the approval.(I797). If your h-1 is less than 6 years, of course you can extend it. about if you can submit i-140 based on approved labor, I don't see why not. still same employer supports you. But I am not sure, I just knew some colleges went back home country with new H-1 while their labor was still in processing. I saw some India guys ofter aboard with their multiple entry H-1 visa and seemed never adversely affect their green card processing.