In-combat healing sucks. Like, really, really sucks. Playing a Healer, you'll want to be able to do something else in combat, say, crowd-control or heal while dealing damage. That means... Multiclassing time*.
Go
Human
Stats: Str 14, Dex 12, Con 14, Int 10, Wis 8, Cha 18
Your first level should be, confusingly, a Crusader level. Yep, a Crusader. Grab a guisarme (reach + trip), get a spiked gauntlet, now you threaten in 10ft radius.
You can heal with your Martial Spirit Stance + Crusader's Strike - they're good enough for early levels. Then you enter Healer... For 4 levels.
Lots of undead? Great. Being Crusader1/healer4 you enter Crusader for a level, then immediately follow by three Knight of the Raven levels. Now you added the Sun domain to your spell list, can turn undead (that's something you should NOT be doing, instead grab Travel Devotion and jump around the battlefield, positioning yourself strategically).
Being Crusader2/Healer4/KotR3 you may think "Hey, I want more spells on my list". Good for you. Enter the Prestige Paladin. One level dip is all you really need - it adds a caster level and ALL THE PALADIN SPELLS to your spell list. Now you can re-enter KotR and be happy... Or enter Ruby Knight Vindicator and be happier.
Feats:
1st: Dynamic Priest
3rd or 6th: Mounted Combat, the other is open
9th: Travel Devotion. Or something else.
*It actually works better with Favored Soul and 3 PrPaladin levels, due to the nice Charisma synergy that ensues.