Might have been a fluke, but we once got cellc 3g from a vodacom tower in the Greenbushes area. Don't know what happened there, or how it happened... and this was before cellc rolled out their 3g network.
Best you can do is to cough up and get a voda prepaid SIM for country use. GPRS/EDGE is not usable at all - take it from me. You can only do basic IM like gtalk/skype, but web browsing and other things are totally out.
And don't use Windows, rather use Ubuntu/Linux to minimize bandwidth "noise". The less you try to pump out to clog up that tiny EDGE/GPRS pipe, the better.