In order for the hosted wireless network to work you need to use a
Windows 7 approved driver which will install the
Microsoft Virtual WiFi mini port, this mini port is what allows you to create the hosted wireless network.
I'm not too sure about how this will work through a broadband dongle.
This link shows you how to set up a hosted wireless network both manually and using the connectify software.
http://www.winsupersite.com/article/...ion-wirelessly