You can get the o-rings and carriers, shims, and dang near everything you need from many aftermarket places.. Tunamart
or e-mail email@example.com
I have ordered tons of stuff from both places and have never been unsatisfied. They will be cheaper then the AGD store too (they have jacked their prices since they moved into Zupe's basement).
Just tell them what you want, and they will give you a quote.
Hope that helps.