There are routers that also have USB - 3G capabilities. Usually advertised as being a back up to the ADSL functionality of the modem... but can work just as a router for the wireless USB modem just fine.
http://www.billion.com/product/3g/bi...l2-router.html
http://www2.netgear.com.au/au/Produc...dband/DGN2200M
There are others too....