Level up a 5th shaman as resto on the paladins acct? Or maybe better, a resto druid, instant travelform! Batterez! Innervate! Respec to Moonkin for Trees!

Or just keep him as Prot, cause often, people go after the "head" of the snake of multiboxers, and a prot paladin takes a while to die... And after the 3.0 patch, my prot paladin can do a decent job of off healing, even in prot gear.