Yeah, I knew what you were talking about, but still have never seen one for sale as a separate piece. You probably have a converted switch, or one of the many manufacturers does, or used to, do it that way.
Is yours set up to be a lighted switch by any chance? Extra tabs anywhere not being used? Extra holes for a light bulb? That's what that type of ring usually says to me. You see them on the lighted cigarette lighters too.
Hmm, maybe you can pick up a lighted lighter from the accessory store and use the one from it? Assuming it's got all the same notches and tabs of course, but the diameter should be pretty darn close I would think.
Just a thought.
Personally though, I think that, if it didn't come with the new switch, it isn't needed in the new swtich.
Are you going to try to stick with the old (now broken) switch? Or use the new one?
Paul