They are under 10$.. Either one of them online rovershops will give it to you. I got mine from britishpacific.com where i am normally shopping for parts. Being in Santa Barbara you can just walk to their shop (they have one of shops somewhere close to my recollection) and get it. They have about best prices for lots of stuff and shipping promptly.
If you feel like waiting a tad - you can get it from any shop like RoversNorth or AtlanticBritish or NorthEast.. But i would think you need it pretty soon - so just give them a phone call. 800 554-4133
Oh and i used black RTV and cork gasket on mine - seems to be holding well so far
