let me know what you find. I've considered rafting down there on a lilo with climbing gear and food / gear for say 2-3 weeks from Newnes (Wolgan Valley) but never found anyone mad enough to go with me.
There are some web sites that have a little info on canyoning in the area as well as some environmental groups (i.e. Friends of the Collo - http://adunk.ozehosting.com/foc/ or via e-mail FriendsOfTheColo@optusnet.com.au) but in terms of climbing I don't know where there is any info. Not sure how much has been done.
You might like to talk to some of the dudes from the SES.
I've been down the Wolgan Valley as far as Master's mountain and the Wolgan Pillar. It's an amazing place and well worth the (5-6hr) walk. There is so much (new) climbing to be done in this area. Due to it's access it's unlikely that many people will be bothered though.
Good luck planning your trip. It looks like a brilliant place. May I suggest you take an EPIRB.