It sounds to me like he is talking about a wireless broadband card. That would also explain the 'usb router' requirement.
, there are no routers that you can just plug a mobile broadband card into and go. It would be incredibly difficult to manufacture such a device, and it would have to be updated for every new card out there. So I doubt it exists.
What you can do is plug it into your desktop, plug a normal router into the ethernet port, then enable internet sharing.
BTW, I don't recommend using a 3G card as your main connection. The ping times are painfully slow, and it tends to get severely congested at certain times. If it's on WiMax, then I guess it'd be okay.