Here is what to do, wait until 2am game time or so; use an invisibility potion, or any other sneak power. there is a shout and also a vampire stealth power available to you. Once stealthy sneak into a house find someone sleeping. sneak up to them as if to pick pocket once you have done so you will see an option to feed, do so. Now you are back to a stage one vampire and are free to walk unmolested amongst the living again. Next go to the tavern ask the bar keep if they have heard any rumors, at this point one of the rumors should tell you about a mage that studies vampires. this will start the quest to cure vampirism. In my case the first bar keep I asked gave me the quest, your results may very.
GL