H4 Visa with I797 approval notice - Urgent

[Madhava]

Hi,

My Dependent stamping is on 17th Jan '2017. I am in USA and my VISA got expired but I have a hard copy of Approved Extension petition(upto Jan 2018). My question is,

- when my wife going for stamping(17th) Before that I need to get it stamped or is it fine to they Can attend the stamping interview with the Approval Notice copy?

Please provide your input.

Thanks,