Although I can't find it now, I thought I read that you had a cellular wireless card that worked with a notebook computer.
If that is the case, you can always use that same card with a desktop computer. It could be a solution if it gives you a faster speed.
If it is USB, just plug it in.
If it is a PCMCIA card, they make a PCMCIA card slot device that fits in an empty PCI card slot on your motherboard so you can insert that card from outside the case when you need it and remove it when you want to use it with your laptop.
New desktop computers with Win 7 on them can be had for as little as $400 (a decent machine, not the bottom of the line). I've bought a few HP Pavilion machines over the past 3 years and paid no more than $500 for a business grade machine.
Some places to look are tigerdirect.com, newegg.com, microcenter.com, woot.com (usually one deal/day so you just have to hit it right),
Deals.Woot : One Community, Every Deal (SM) (shows multiple deals and will point to some of the other links I noted above). I've bought refurb desktop computers thru some of these and have had excellent luck (I've repaired/built computers for almost 20 years so I didn't see a downside, although both machines have been flawless).
Just some ideas to think about.