Once upon a time(back in the 80's), there were quite numerous shops on the Peninsula. "Frahs" in San Mateo and "The BoatWorks" in Belmont both used to get my business. Both are gone now.
If you want to travel to San Jose, there is Glen at Pleasure Boat Specialties. He is well known to many in this area and a nice guy, to boot.
A little farther away would be GT Boats in Cordelia(where 680 and 80 meet). The new owner is a local ***boater. Company has been around for decades.
Depending on what kind of parts you need, you may find them at any local boat shop. For more performance oriented stuff, you can try Vic Hubbards Speed and Marine in Hayward. They're right off 880 in Hayward...East 14th Street, I think.
Online, you have lots of choices. Rex Marine seems to have the best service. CP Performance in Rohnert Park is good, but it seems to depend a lot on who takes your call. I'm close enough to drive there, so I rarely do mail order with them. If you're going to make a trip up there, have them pull the part FIRST.
Sounds like you are already enjoying the new-to-you boat. You'll have to make it out to some of the local get-to-gethers.