I'd hold off on Persistent spell for a long while. Among cleric spells, the real winners for persistence are the three already listed. One is first level, adding a +1 luck bonus to damage & attacks per three levels. This will be at a minimum of 11th level (with your levels of Templar and Paladin) .. but it will cost you a flame strike to do, and only give you a +3 bonus to hit and damage (though it stacks with most everything and lasts all day). Divine Might and Weapon of The Deity are the other two good choices, but they require 8th level spell slots, something you won't have access to until 17th level….
As far as other spells, Persistent Spell is useless if your DM lets you Extend a spell more than once on anything that lasts an hour a level. Why use a Persistent Bull's Strength when an Extended, Extended, Empowered casting gives one and a half times the benefit, and (since you'll be at least a 13th level caster) lasts at least 13x3=39 hours?
(Note I have a personal vendetta against Persistent spell, as a poorly designed, very poorly balanced feat that's either fully useless of overwhelmingly powerfull. There's nothing in the "common rules" (I'm so glad it didn't make it into the core rules) that annoys me more… So take that advice with a grain of salt.)
As far as the rest… Hospitaller's really need armor of speed. The only way to complement a cleric who gets a base attack bonus of a fighter, Lay on Hands, Two fighter bonus feats (4, but you need to take two before you can get into the class) and free castings of remove disease at nest to no significant cost (10 skill ranks in ride & handle animal and the bad will save (HAH!) are the worst of it, you get the feats back, you keep your full spell progression, keep turn undead advancement. All you MAY loose is the odd bonus to your domain abilities for cleric levels, though not with the ever popular War as well as half the other domains. And there's an alignment / code of honor restriction… uhm… yeah.) is with an armor enhancement that provides a +4 bonus to AC AND a non-dispelable permanent haste spell (You can suppress it, but you can't dispel it) at the cost of a +2 enhancement. Man, must have taken some real solid team of Designers, Editors and Play Testers to get all of that into Defenders huh?