Master of Radiance - Aura question

[Mailce]

Hello everyone. I am planning on playing a Master of Radiance build in an upcoming campaign. I've read it's not the greatest, but it sounds like fun. Anyway, Is there anyway to improve Radiant Aura, specifically duration? I've seen Enlarge/Extend Supernatural Ability, but I'm looking for more. The build will likely be Cleric 5/Radiant Servant of Pelor 10/Master of Radiance 5 (not necessarily in that order). Any other suggestion welcome. I'm trying not to go to crazy, we have 2, of 4, new players.

Thanks in advance for the help.

[Gildedragon]

Well there is widen, to increase its area, and empower to increase numerical values by 1/2