Make your job much easier
You can buy Granado Espada vis in mmogood.com. Generally if you combine your mitigation and defense buffs with your heal and host you should be able to keep your group up through most situations, minus heavy AE boss fights or with a tank that is heavily under geared. Telling you are squishiest to stay out of AE range will make your job much easier.
For example, I did solo heal a group of 4 Sins and a Gladiator Tank against a level 47 Elite Quest boss with heavy AE attacks, and quite a few special skills including ads when I was level 42. The group however knew how to use Greater Healing Potions and in general helped with the overall outcome.