Can you buy this from a local gaming store? :-\
Nope, buy it online.
No. Check ebay. But you should check out Dazzle as well. In my opinion it is better than a Gamebridge.
No, buy it online. From my own experiences with the GameBridge, the frame rate and picture quality of the game itself depends on your computer specs.
In short, if your computer sucks, don't get it.