Custom Made Foot Beds, are real orthics as Faller has suggested while be your BEST option.
But if your short on cash and want a quick fix whip a pair of these in our boots:
http://www.superfeet.com/content/product.html
Superfeet:Peformace Line.
I have some in my boots, and there a WAY better, i put them in my shoes too sometimes. Anyways there only like 40 bucks Max, and help alot.