|The Nite Owl|
As already noted, a two-handed sword would increase your base weapon damage and your power attack bonus, but it would mean losing your shield.
At 7th level, with your charisma bonus to spells, you could take Litany of Righteousness. This doubles your damage against an evil creature - but it's only for 1 round - so best saved for tough opponents.
Your character seems pretty well optimised. If the gunslinger is outdamaging you, I wouldn't be too worried - it's his only trick. Let the baby have his dummy. A paladin can swift heal himself in combat, has the best saves in the game and with skill points in Diplomacy be an effective party face too.
For future characters, you might be better using the point buy system, or make a rule that ability scores have to be rolled in front of witnesses to avoid the bs stats.