Can I make my laptop run a WAN?

Let me explain. I have a laptop in my car which has internet access through a mobile broadband device (usb dongle from Sprint). While this is great for me, since I use my mobile office laptop to communicate with clients, access my SlingBox at home to watch TV, take Skype calls, listen to iTunes, watch DVD's on long trips, place bids on projects and so on.

The problem arises when I have the family in the car... two teenage daughters constantly wanting to check their facebook accounts and a pregnant wife who wants to go online and play, plus several other wireless devices, an ipod, etc... and I start to want a wireless network on the go.

A typical wired/wireless router uses a 10T wire from the cable modem... then the wired connections as well as the wireless connections are all connected to the router, right?

Is there a wireless router which can connect directly to my USB Modem Dongle? or is there a router which can connect to the laptop and just connect to additional devices from the connection formed on the laptop?

My question SEEMS simple but I've yet to come up with a solution... what hardware do I need to set up a router without the 10T connection to the modem?

Any advice would be appreciated.

~a

I believe they make a portable wireless router that will accept your mobile broadband device.

Grumpy