You can get IJP clothing at ianpoulterdesign.com. When you go to the site, click the US flag and the prices change from Punds to Dollars. Then you can shop away. Not all of the paints shown here are available on his site. It seems that they clothes are available at various increments during the year. You can also find IJP clothing at Zappos.com. I got a pair of his shorts there a few weeks ago.
FYI, the clothes are fabulous and just fabulous fabrics. If you buy from Britian, you will be charged about $25-$30 shipping, but the products come DHL Air shipment, so they show up in about a day. You can also check and see if there's a l ocal green grass shop that carries the stuff, but it's usually priced a fair bit higher. I know that Doral has his stuff in stock, as I saw it there earlier this year.