new holy priest used to be shadowFollow

Hello, I need some quick help and I was hoping you could answer a couple of questions for me.

I recently dinged 70 on my priest and up to this point I havent healed or anything, was just levlling shadow. I'e tried to heal a few instances now and a guild firend said I should get the primal mooncloth stuff, so I'm saving up for that.
I want to heal in normal instances and maybe heroics, my guild is doing karazhan soon as well. Im really enjoying it but because I was goin to stay shdw at 70 I dont have any healing stuff.
I tried to heal in slabs the other night and I had quite an issue with it, I wanted to know where I should go to get some new healing equipment, which instances should I be doing, which are going to be the easiest, should I go back to some lower ones and get some stuff there first?

I hope someone could give advice on some nice stuff I could get and where to go, im the only priest in my guild at the moment and I want to imporve. Thanks for reading!

There is a post on Page 1 of this forum titled Holy Priest - Gear - Heroic, Pre Kara and Kara Upgrades . I recommend you start there to gear up on healing stuff.