Assistance Required: Travelling to India on unexpired H1B visa stamping from ex employer

[H1BTransfer31]

I currently have a H1B visa stamped through my ex employer and valid for one more year until Dec 2016. I have changed my employer and got a new I797. I am considering to travel to India next month for 3 weeks.

 

My questions are:

 

1)      Can I use my existing H1B visa stamping from old employer and approved I797 from new employer at port of entry? Is this fine or Do I need to get a new Visa stamping?

2)      Also, which date would I get on I94? Visa stamping expiration date or new I797 expiration date? Please suggest

 

Any suggestions/recommendations as part of documents to carry are most welcome.

 

Thanks!