Taken from the website of Australia Network:
http://australianetwork.com/tuning/reception.htm
"If you are receiving Australia Network directly from the PAS-8 satellite you will need to alter the Transponder, Frequency and Symbol Rate details by December 1, 2006. Please note if you are receiving us via another satellite you don't have to do anything. Also if you receiving us via a rebroadcaster the rebroadcaster will be notified directly about the changes they need to make."
This means that you will need to rescan your satellite (PAS8/PanAmSat8 at which the dish is probably already pointed) for the new frequencies through the menu of your receiver/decoder. Or you change the settings that are published on the website manually in the receiver menu. But search for your settings or setup menu and look for a full transponder-scan. It will update and store all channels automatically to your receiver in less than 5 minutes.
Good luck.