Skulhead, you won't find it. It's a Series 3 figure. Evil Ash is a Series 4 figure. They're already working on Series 6.
In other words, it's discontinued, and you won't find it in any toy store. Try a comics and collectables store. Although I advise against it, because that figure is very lame.
You see, they will be releasing an Ash/Evil ash 2-pack in the near future, so it's better off getting that. I'm going to, because while I have both figures, the Ash I have didn't come with accessories (because he doesn't need them; He's that hardcore).