There is a new Telstra approved "smart antenna" which repeats the 3G phone and data signal simply by installing the antenna to a window, fully approved in Australia and works for phone calls and 3G internet service.
From memory they are about $500-$600 and would work well for you there.
The supplier I know of (no interest in them) is
www.powertec.com.au.
Or check out
www.cel-fi.com.au or
http://www.telstra.com.au/business-e...smart-antenna/
Cheers
Chris