Good luck.
I had the problem last year after re-assembling the bike without replacing the o-rings and was really scared by the amount of oil that had distributed itself around my rear tyre. Damn dangerous.
I pulled the shaft (because I didn't have anything to remove the o-rings without damaging them and it was about 30 minutes before the shop closed on a Saturday), went to a really great local auto-supplies store where they matched them, charged me about $1 and no problems since.