I know in Washington it's the top vote getter from the top two parties, not the top two vote getters - isn't that the case in CA now too?
In Washington, it's the top two candidates regardless of party. We haven't had any major races that haven't been D vs R yet, but we've only been using the system since 2008. We've seen some Ds and Rs eliminated when they run in a very solid district for the other party, though. The only notable exception I can think of off the top of my head is a State Senate race last year that had two Ds and two Rs, with the two Rs moving onto the general.
...But yeah, back to California! So it seems to be generally accepted that Brown won't run for re-election?
No, he's been asked about it several times and he says it depends on what gets done and what the situation is like in 2014. Basically he hasn't ruled it out.