The aura button plugin is here :
http://www.wowinterface.com/download...raButtons.html
nUI's buff situation is as follows:
Lower left (lists or buttons) : Player Buffs
Lower right (lists or buttons) : Target Debuffs
HUD left (buttons) : Player Debuffs
HUD right (buttons) : Target Buffs
Easiest way to think of it ..
Player Left, Target Right, Good Bottom, Bad Hud
Hope that helps