There is no new version of the Bungonia guide at the moment. 'Strangeness and Charm - Rockclimbing in Bungonia' edited by Mike Law-Smith is it. Unfortunately you won't find it in the outdoor stores in Canberra - in fact my copy (which is a copy of a copy) is currently being copied by one of the staff from Paddy Pallin's!
However, the Sydney Rock Climbing (SRC) crag is probably what you are after for top-roping, and the best info is probably at the website that Rich mentioned, although the guidebook does have an additional description and sketch map to help you find it. You can see it when you look right from Adam's Lookout. There is no distinct track to it - when you locate the ridge that it is on, you can either skirt down a gully on the left (facing out to the gorge) and cut across to base of the buttress to the right, or from a clearing at the top of the ridge, head straight down the ridge until it gets steeper and rocky, then scramble down left to the crags base. I haven't set up top ropes there so can't give you any info on that.
You may want to contact the Sydney Rock Climbing club if you want further info, since they pretty much found it and used it for group trips. It doesn't look like it gets frequent traffic due to the lack of tracks.