I didn't find any resource for this when I searched so I thought I'd follow up with a link to some instruction.
formatting link
You can absolutely use a Speedtouch USB modem without too much trouble if you follow the linked instruction. Basically, Internet Connection Sharing (Windows) sets the Connected computer's IP address to (192.168.0.1). In order to set up a network that is compatible with this, you may have to change the ip address of your router.
Or, you can get an ethernet modem and make life really easy. I'm just offering options