Unfortunately, all indications are that you need to buy it when you get to Australia. I checked the store locator on their Website, and they only offer it locally. In addition, I checked to see if you could order it online and have it shipped internationally, which also was a dead end. This is not unusual though, for wireless products like this are usually sold only in service areas.
You could try purchasing it online and having it shipped to a friend in Australia if you're staying with them, or perhaps have it shipped to your hotel. If you go the hotel route, I would recommend calling in advance to make sure they will accept the package, particularly if it will arrive before they have a record of you being checked in. I've done this before, and it worked out fine, though it always makes me a bit nervous that it will get lost.
A caveat to ordering online is that they may not let you use a credit card with a foreign billing address. I know I had this problem when trying to order product in Europe with a U.S. credit card, so that may not work out for you. On occasion I've got around this issue by calling their support on the phone; some companies will be able to take foreign credit cards manually over the phone, even though they can't accept online orders.
Lastly, if you have a postpaid wireless broadband service in the U.S. or Canada, you could call them about international roaming rates or plans. However, inevitably, you'll end up paying MUCH more than getting something locally down there. Hopefully in the future North American prepaid broadband providers will provide more competitive rates, however, for now it's not likely a desirable option. I have yet to find a prepaid broadband provider in North America that will allow international roaming; it's usually a cost issue.
Anyway, I completely understand your objective. There's nothing worse than traveling abroad and wasting your precious vacation time looking for cellular or mobile broadband service! Thankfully many countries these days have these services really available, so hopefully it won't be too much of a pain.
After you come back from your trip, please check back here and tell us about your experience!
