eBay. You'll need the flange plus the circlip.
Your talkin 15quid for a 34mm universal flange and 8.50 for the circlip and you'll need a silicone hose to join it to the intercooler pipe. I've had a few different types on mine like type s and sheepdog and I've jut fitted an ssqv 2 and it's my favourite so far.