Some power proc gear:
Heal/DPS:
Girdle of the Di'Zok Spirit - Chardok rare shinies
Heal:
Ghatachonoth's Energy Siphon - The Blue Baron (Chelsith)
Battlemaster's Rhino Hide Chaps - Selnok Brigade Faction Item
Reet Tongue Fingerwrap - From one of the Wheel faction quests in KJ.
Horrific Signet - Gruplinort (Crypt of Agony)
DPS:
Soulsiphon Leggings - COA / Sebilis
Lava Forged Manacle - Scorpkis questline in JW
Foreboding Cowl - Librarian Zimor (COA)
Slythe's Vestment of Trickery - ?
Swamp Glow Wristcuffs - From one of the Wheel faction quests in KJ.
Manawell is very good for heal heavy situations, as it is like OLH in that it can proc once for every group member on a group heal. You can probably get away with using Manawell items for DPS too if you use your group heals regularly to proc infusion.
The Chardok belt and 2 Manawell items would probably do wonders for your mana regen.