You can order replacement gaskets direct from Kokatat if you're having a hard time finding a replacement. Something to consider keeping around is Tear Aid (my review: http://www.paddlinglight.com/reviews/tear-aid-review-an-emergency-repair-kit-and-patch/ ). It works as an emergency repair patch while you're waiting for the gasket. It's good stuff that helped me finish an expedition this year after my gasket ripped about seven days before I finished.

Replacing a wrist gasket is easy. Necks are slightly harder, but still pretty easy to do. Good luck with your replacement.