H1B extension and H4 travel

[Satyakumar]

I am on H1B and my visa expiry date is 'Dec , 2016'.

My spouse is in India. I have initiated H4 for her and she got her PA date (for Stamping) on '27 Sep, 2016'.

As my wife got her PA date in end of September (closer to my visa expiry date), at which point of time...

[jmahmud]

My H1B (first time) approved, and USICIS has sent me the approval notice.
My wife is in my home country. She needs to apply for H4 visa. Can she do it now or does she need to wait until October, (since my H1B starts from Oct) ?

Please advise.

Thanks

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