Telstra Wireless Broadband 7.2 USB2 Mobile Card VS Mxon Blue Modem

I know communications have been done to deathin the forums but I admit to reading everything and still being confused. I know that we need access to the Telstra network for the best phone/broadband coverage. We don't have a Telstra mobile but would like to have access to the internet in most places (including Skype). We are doing a full year's tour of Australia so will need it in the fairly remote places. I wanted to buy a Telstra Modem but the one that many people have recommended (which I think is the Maxon "blue toaster") is no longer readily available. The new one is the 7.2 USB 2 mobile card from Telstra, which is more expensive. We were thinking of this option linked with an external atenna, but if it is no better than the older blue modem, I don't want to spend the extra money (old one around $99). Does anyone know if the new 7.2 USB modem is better than the older Maxon......also does anyone have any idea of what type of distance an external atenna will extend the signal by. Thanks for any advice