If you get ANY signal through, you can use a signal booster, like CelFi: http://cel-fi.com/ . All they need is electricity and a window (to allow decent GPS signal).
They're 500$ new, 200-400$ on eBay, and free with T-Mobile subscription of 18mo (and dealing with some phone bureaucracy. This may seem like a lot, but it's a lot cheaper than paying 750$/yr more for data with AT&T, plus it will benefit your whole office.
They're 500$ new, 200-400$ on eBay, and free with T-Mobile subscription of 18mo (and dealing with some phone bureaucracy. This may seem like a lot, but it's a lot cheaper than paying 750$/yr more for data with AT&T, plus it will benefit your whole office.