For healing I use Healer's Habit/Eyes of Mara, all light (NB, so 12% resto staff reduction works better for me).
You should not be dying if your group is keeping aggro away from you and you are blocking when they don't.
You may want to add a piece of heavy, but I'd still go with mostly light armor, unless your mana pool never goes below 50%.
Alternatively, you may need more health? What's your health like?