Here's your parts list, pilgrim! (download the PDF)
Tech Knowledgebase - Installation Manual for TRD 3.4L V6 Supercharger
Go to Page 2... That's the list. If it's on the list and you don't have it, that's what you're missing. If all he's got is what's in the picture, you're missing pretty much everything.
Edit... just so this doesn't come across like I'm being an ass, the main things you need are:
1. Dynamic Tensioner & Hardware (you can get this separately, online for $275-300)
2. Longer Alternator Belt, which drives the S/C (about $20 @ any Toyota Dealer)
3. 1-Way Check Valve (this is IMPORTANT to have, prob have to buy from Toyota Dealer)
4. Hardware to bolt the S/C to the intake manifold
5. TRD "O" Shaped Throttle Body Gasket (about $15 @ any Toyota Dealer)
I can see the support spacer for the S/C in the picture (Listed as
Spacer, Manifold Support Bracket in the manual)
I can see the bracket for the throttle/transmission kickdown cables in the picture (Listed as
Bracket, Accelerator and Transmission Cable in the manual)
You can re-use the gasket on the intake manifold when you install the S/C, assuming it isn't torn up. The gasket between the upper and lower intake runners is the same as the gasket between the lower intake runner and the intake manifold, you can use either one, so if one is torn up you can use the other.
The rest is an assortment of vacuum fittings, hoses, and hardware. Given enough time and determination, you could peice it all together based on the list in the install manual.
Last but not least, that thing looks pretty oily on the bottom of the nose cone. If that nose cone is leaking, you'll need to replace/rebuild it. Replacements are about $300 for a kit.