I know this is an old thread but......
I found this area while browsing the Nearmap photomaps site.
This is just to the west of Bundaberg and north of Miles/Toowoomba
http://www.nearmap.com/?ll=-24.85902...h&nmd=20040101
It looks about 4km across.
Hopefully the link will work and you can zoom out and see where it
is roughly.
What is this?....Any locals know what this circle is?
Two posts below Steve (Gargoyle) has a link to most of the
Australian impact sites....
A map is shown here....scroll down
http://www.passc.net/EarthImpactDatabase/Australia.html
Steve