You can send an e-mail to info@luminahealth.com and ask them if they sell Cell Food at any retailers near you.
A number of people have posted around here that they are distributors for ThreeLac and Hydroxygen Plus. Scan through this forum and contact some and see if they're willing to ship to Australia. (I'm not listing addresses of any so as not to play favorites. Sorry!)
Also, I've discovered some oxygen supplements which are manufactured and sold right in your back yard. Check out these sites:
You can probably find more via Google or another search engine by entering "oxygen supplement Australia".
One last thing: I've noticed that after my initial cleansing behavior, I've actually seemed not to have bowel movements during the fast while including the oxygen supplement, unless I eat (i.e. I break the fast). So... you might find yourself still stuck needing some salt water or laxative tea (which doesn't work any more for me, either... strangely enough...) for intestinal cleansing.