ZZP, Ebay, junkyards, classifieds. Any brand new kit is going to be the same parts that GM used on the Supercharged Cobalt SS's. I think we have a thread somewhere covering supercharger install on a 2.2/2.4 or atleast have the install instructions posted.
This is a write-up my buddy made years ago for installing the same supercharger onto a Cavalier or Sunfire. Everything will be the same aside from the throttle body.
If the supercharger has a black pressed on pulley(no bolts), it is the stock pulley. Aftermarket pulleys bolt onto a quick change hub. If you see any bolts on the front of the pulley it is aftermarket.