You will need two networking devices. Your Aircard will not receive the signal and re-transmit it to other clients.
You are right, the Aircard cannot re-transmit the signal to the clients. I want the gateway/router to do that.
The Aircard is not a wifi device in this situation. It can be used that way also if you are at the local coffee shop that is an AT&T hotspot. That's not the case here. When inserted into a pc it becomes nothing more than a dialup modem. I can use Chestnut-dialer, Minicom or any other dial up app to connect to the AT&T cell phone tower. It is seen as "ppp0". I actually use chat scripts provided by Sierra to connect because the Aircard has a full complement of "at" commands to work with it just like a dialup device. A simple "pppd call gsm" hooks me up. All the client machines already have wireless capabilities. The desktop box I want to use as the gateway/router doesn't. I'll hang one off one of its usb ports to make it wireless capable. What I looking for I guess is...
Are two wifi devices required in the gateway in this situation?