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I would recommend updating your device to iOS 7 if this has not already been done. Once you have updated the device, see the steps in the article below.
When you setup GMAIL on your iPad did you also ask it to turn on contacts? It would normally do this during the last steps of the email setup process?
If unsure go to Setitngs>General>Mail, Calendar & Contacts>emailaccountname
Is the switch for Contacts Green? If not turn it on from here.