Look into Virgin Mobiles (Australia) or other companies. It may be cheaper to buy a pre-paid mobile phone than to rent a mobile. At least that is the case in Europe. Another option is to check on Ebay. Someone may have bought a mobile there for their trip and now is selling it. You may need to get a sim card and add time. If you buy a mobile, it can be mailed to your hotel. Then, you can sell it after your trip on Ebay.