Lost H1b I797 approval original document

Hi.

I traveled to USA in 2014, with I797

Later, I got extension in 2015 which is valid till 2017. I received an approval notice of I797, which recently I got to know that I have lost.

My extended visa is not stamped.

Now, after my amendment was done in 2017 for another location, I am going to travel again. But this time stamping is required, which is due next week.

When I started collecting documents, I came to know that I am missing latest I797.

I do have a xerox copy for the same.

What should I do, interviewer would definitely ask for approval copy.

Would xerox copy suffice. Does my employer have another original version of current I797.

Need to reach US asap coz of business need