USB internet key into airport?

The only way i can get broadband at my place is by using one of the 3G vodavone USB keys into my MAC. And at that only upstairs in the front room. Long story but thats the only way, ive gone through them all and there is no other signal.

Anyway i was wondering if i got an airpot express and but the 3G key into the USB slot on it would i be able to create a wireless (using its signal) network for my MAC and a PC. Not using both at once just the Pc has things i need for work from a few years ago.

Any help would be great, thanks......

Can anyone help me with this?

The USB key can't function by itself, it creates a Network connection for its host Mac or PC. The Extreme or Express (or any wireless router) can't be configured to access the USB key, so the answer is no.
I suppose you could rig the USB key to handle the connection and use a wireless card in the Mac to provide a household wireless signal through Internet Sharing. But that would mean the Mac would always be in that upstairs front room. Internet sharing is a bit of a kludge, but it should work.

thanks for that.