Can I apply for a Gold Seal any time, or only when I renew my CFI certificate? Basically my CFI certificate expires almost a year from now, but I have met the requirements for Gold Seal. Can I obtain my Gold Seal now, or do I have to wait until its time to renew my CFI?
You can apply now. It will be reissued every time you renew your certificate.

http://www.pilotratings.com/goldseal.html