This seems like quite a complicated model for an internet connection but I can tell you now that it is possible, just complex.
If you did get a wireless router (I'd recommend the Linksys WRT54GS) you could network the two computers using your wireless connection then it would be a matter of sharing your laptop's wireless network connexion. It isn't the greatest way to go because you'd be effectively not using any of the hardware firewall that is built into the router... But it would make it so your computer could access the internet at the same time as your laptop. You might also have to do a network bridge and stuff depending on how that aircard works.
This is a particularly complex setup and I wouldn't recommend tackling it without any prior networking experience. This all sounds fine and dandy till you try it out and something goes wrong. There is a strong possibility you'll have to work around firewalls on both computers as well as switching the router mode so it doesn't act as a gateway. Also there is an entire new layer of garbage to work through if one or both of the machines happens to be Vista.
Another suggestion if you do try this is: Purchase the router at a big chain store like best buy or staples -- they oftentimes have a 14-day money back guarantee so if you do try it, and fuss with it for a day or two and dont get it working, then you can return it and all you're out is the day or two