Lonely Boy Needs A Home - When, Where?

Hi, our other budgie died yesterday and now we just have one. We don't want to take yet another bird so we'd like to re-home him... He's never been alone and he's also used to being able to get out of the cage and fly (but he's not very tame) so I suppose an aviary would be a good solution. The other bird was only 5 years old, but I haven't managed to think of a reason why he died. He seemed completely normal up until I found him on the floor of their cage when i came home from work.

Questions:

- How long should I wait before giving the other one away, what do you think is the quarantine time here? I'm feeling sorry for the lonely *******... He's a rather active little thing, even a bit bossy but very timid without other bird company.

-What do you find is the best, most reliable way to re-home your pets safely? If there is someone here with a good reputation, known to be "real", and is interested, please let me know He's light yellow and blueish gray with clear black markings . He's 2,5 years old.

(We live in the Sutherland shire, southeast Sydney.)

Thanks!