Wow... I like this set. It is certainly very reminiscent of a more classic Horde, especially with that staff. I agree with what others have said that the shoulder piece and the helm don't exactly match, the quality differs too much there. I would recommend maybe... Tier 13 Shoulders (might be too big, but it's a possibility as it matches the colour scheme nicely. Helms that go with this kind of set are hard to find, and I'm pretty picky with it. If it doesn't go with the colour pallet, it doesn't work.
I would say this helm could work very well with this set.
http://www.wowhead.com/item=29136/far-seers-helm
Here's the Tier 13 set.
http://us.media5.battle.net/cms/gall...6046818760.jpg
Threw this together using the items that you used with the different shoulders. Could use a different helm if you prefer.
http://wowsets.com/set/9TKBSx