Big problem. D: Trying to share an internet connection from USB broadband connection. Please help D:?

[Aenima]

So this is what I have:

T-Mobile USB broadband stick.
2-Wire wireless router.
Nintendo DS
Mac computer

Basically I want to share the connection from that wireless broadband to my Nintendo DS. But to do that I need wi-fi, which I suppose is what the router can be used for. But to use the router I would first need a connection from my wireless internet USB stick to my Mac, and from my Mac to my router. I have no idea if it's possible or not. D:

If that's not possible, is there a way to connect directly to my Mac wirelessly and share an internet connection that way? The thing is that only whatever the USB is connected to can access the internet, but I'm not sure if maybe my mac can share the connection or not... My Mac has this function called "airport" i'm not sure if that is helpful or not.

Pleaaase help, it's been bugging me for days. 10 points will be awarded thankkkks.