Honestly, if you are new to PvP you want to focus on survival. High mobility and/or high passive defense should be your goal. Once your enemies figure out you are the healer, they will be coming for you! And a dead healer does no healing Personally I like some of the heavy sets that provide extra armor and defense. I think Daedrick Trickery and Pariah are two fairly good options. But neither of these are craftable. If you get into more coordinated play however, your raid leader will likely dictate what gear you will run in order to maximize the group's total strength. For now maybe just strick to some basic sets that increase your sustain and defense. Armor Master, and Fortified Brass might be ok for some defense. Seducer's is a good option for helping out your sustain.
Keep in mind though, sets alone aren't going to keep you alive! Survival comes from active play too. Part of this comes from experience and awareness of your surroundings. When I first started out, my friend took me into Cyrodiil right away at level 10 with a mostly naked toon! When you've got literally nothing to work with you start to learn how to read situations and react ahead of time to avoid being overwhelmed. So this should be your first thing. Just learn how the ebb and flow of combat goes.
HtH!