http://www.priceusa.com.au/ will buy the product for you and ship it to Oz - I haven't used them though so I don't know what the service is like. There's also 10% gst to pay.
I was told by a reputable source that Celestron prices were going to drop in Oz by up to 30%, but that hasn't happened yet. Might be worth calling an authorised dealer to see what's going on.