Try www.shockreco.com.au. If they are stock inserts, then as said they either arn't rebuildable or aren't worth it - take the oppurtunity to upgrade.
If they ARE something worth fixing (and are rebuildable - as konis, KYBs, GABs etc often are) - then it is worth it. IIRC it cost about $100 or so to recondition my GAB inserts, but I can't remember. And shockreco DO post.