My Petition is getting expired on 30-sept-14 and have valid visa till 2018

With above visa can I fly to US-So far I haven’t travelled to US,Is there any option to extend the Petition with above scenario, If yes then do i need follow the same process like new H1B visa stamping If anybody has come across the same scenario please help on possible solution and way to go ahead.

Regards,
Vivek.

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