intercooler and piping - ebay.
Turbo manifold - ebay. SSAutochrome bottom mount t2 to be exact. Best manifold for the money.
down pipe - ebay. Try and get one with flix pipe in it.
Boost controller - if you are cheap like me, you can get an ebay manual boost controller and use this write up
zerothread?id=346138 to set it up. If you aren't cheap then go with a trusted name...apexi, aem, greddy.
BOV - circuit sports has a top fuel bov for 65 bucks, but I can't say anything about the quality since I don't have one. I'm getting a forge bov off of craigslist, and if that's not there when I get back home I'll get the top fuel one.
Wastegate is internal, so no actuator is needed...unless it's not on the turbo already. I'm pretty sure the actuator is the gold looking thing that the arm is connected to. Post up a pic of what you have and people will tell you what to get.
Hope this helps, and happy boosting!