I play a defensive minded Healer/Warrior combo, but I find myself in trouble when I want to actually heal, because targets usually use those healing moments to beat the heck out of me. What spell should I use to slow them, or to keep some distance? I am not that high in Alteration that I can use Paralyze yet.

Runes possibly? Although I like going with an ovecharged fireball.

Frenzy if you can get the drop on them. Conjuration if you can't.

Wall of Flame, Fire Rune.. etc. You don't get them until later on, but they are amazing. Plus if you're surrounded Firestorm works great.

I'm not a mage but frost practically makes me immobile. Maybe it would work on enemies?