Employer missed to apply H4 extension and my wife's i94 got expired

[Sai_3114]

Hi...my employer forgot to file for my wife's H4 extension along with my H1B extn (applied in june 2016 and currently under  review status). Both of our i94's got expired on Sep30, 2016. I was assuming we both will get our extensions done by the employer and hence didn't bother much, thinking we're legal to stay being our extension under processing. Now my employer called up and asked where my wife was(in india or usa ) and do they need to apply for her extension too, they realized my wife is out of status since 2.5 months and I asked my employer to file for her extn immediately. Employer says that my wife needs to exit the country as soon as possible for them to apply her h4 visa extension, we have 2.5 month old newborn for whom passport and visa need to be applied and it takes minimum one month at least in order to exit as they said.  In some of the forums I see that h4 visa extension can be applied using an application called "Nunc proc Tunc h4 reinstatement " with out exiting usa. Could you please let us know your suggestions?