I think Australian and British sizes are fairly compariable in that a 10UK = a 10 Aus.
An Aussie 8 is usually a US 4/6, a 10 Aus = US 6/8 etc etc...
I don't know if thats much help lol.
Perhaps if you found a size chart that had measurements on it as well? Generally the measurements are in inches and it may be able to help you a little more. If you google search for them there are a few that will come up.
This appears to be a US one
http://fevervintage.com/sz.htm in which i'd actually be a US 2 *shrugs* Go figure lol.
Here is one that has US and UK sizings on it
http://www.hottopic.com/services/size_chart.asp?LS=5&
Livi