What happened to the avari?

First of all i know i'm asking alot of questions, but i'm far to interested in LotRs to stop now, [img]smilies/biggrin.gif[/img] (ps yes, ive checked the search option for this)
What happened to the avari? I know some of them were taken by melkor and tortured and twisted to become orcs, but after that? did any of them eventually come to middle-earth? Was where the firstborn awoke in middle-earth?
well theres some more questions, im sure ill have more by the time i end the series.

(oh just one small thing, any other new zealanders known if "the history of middle-earth" volumes are availible anywhere here?)