That would be the In Arcadia Ego verse by glasslogic.

Ah that's it thank you c:

Glad to help! :)

Not the story you are searching for, but similar:
http://virtualpersonal.livejournal.com/214073.html

Fandom: SPN
Title: Dark Miracle
Authors: Cas ( virtualpersonal) and Fetish of deans_fetish
Pairing: Vamp!Dean/Sam, AU, not bros
Rating/Warnings: NC 17; bloodplay
Characters: The characters are not ours, we're just playin' with 'em
Concrits: welcome in comments.
Summary: Sam Winchester had come to New York to do see many of the things he'd always wanted to see before he dies. Dean Colt hasn't seen Sam since they were both teenagers learning to hunt. Now he's a vampire who keeps his distance from old friends who are sure to shun or hunt him, until he takes a chance on Sam. Hurt/Comfort.