routing software for a laptop

we have a SlingBox that is connected to a laptop that has a Verizon air card inserted to get to the internet.
we are using the Slingbox to transmit video and audio to our station via the verizon wireless card.
our problem is the Slingbox requires a router between the laptop and its self. The Box gets an IP from the router.
we have tried using just the laptop and bridging the ethernet connections (the cat5 on the back of the laptop and the Verizon card).
but the Box doesn’t obtain an IP so it isn’t able to hit the internet.
So we are thinking that a routing/router program/software MIGHT solve our problems.
Does anyone know of such software or program for a Windows laptop?
Thanks