Normally all you have to do to get anything you buy signed at DreamHaven is to buy it from them and tell them you'd like it signed, and be prepared to wait a little. (Several people have asked about getting things signed at DreamHaven as birthday presents. I'll always do sign stuff the next time I go in, but there's never any way to be certain when that's going to be. So if you don't mind things being late, then chance it.)
The second DreamHaven audio CD should happen a lot faster -- the musical stuff is being done by the producer, Adam Stemple.
And then, if people like them, it'll be time to go back into the studio and record a lot of new stories (although I'd also like to do a live CD. It's more fun when you can hear the chuckles and the sharp intakes of breath).