Get yourself the Emblem of Triumph-Libram, which has 200 STR Proc from Seal of Vengeance/Corruption (Which you should be using on single-target mobs that take longer to kill, eg. bosses). Use your current libram while using Seal of Command (on trash/multimob). I myself have macroed that whenever I cast Seal of Command I equip the PvP-libram which gives AP everytime I use CS and whenever I cast Seal of Vengeance I equip the PvE-libram bought with Emblem of Triumphs.
Considering gear: ArP isn't really that good for us paladins. Neither are items with agi+ap on them (although they may look nice
. Go for items with much Strength, Crit and Haste. Keeping your Expertise (16 Expertise + Glyph) and Hit (8%) capped though.
And yes, get rid of that DM Card: Berserker! - It IS horrible ;D
Actually, 21agi + 3% crit dmg = best meta game, since it requires only 1 blue and 1 yellow gem, a requirement easily fulfilled with a single Nightmare tear. So your 2nd tip is BS. Also it is worth gemming for Expertise/Hit if you aren't capped even with glyph.