Most all Navicores will work with most devices, especially the newer GPS Units. I Recommend you get the latest Navicore on the site you can find, i think its 9.101. You should go with a SE Edition one, as it is customized by experienced users for the best functionality. Most Navicores on this site are Hacked, but some are not and need to be via keygen/ meta Tools.
If you want to be 100% safe, just update to the earliest Navicore required by your Map.
Now, the latest Australian Map on this site with WORKING download is 845.2661.
The Navicores that are compatible with this Map are 8.20x.xxx and up. Any of these should work for you. But your bet off going for the latest Navicore as it gives the best functionality, being 9.101. The SE Edition is sure to work, if you know how to set it up (when i used it, i didn't need to set it up, default settings worked :P)