I seem to be stuck as a werewolf... Serena has cured herself and so cannot give me vampirism. I have tried the Glemoril witches heads again but this doesn't work. Is there any other way to become a vampire so that I can get the perks?

In order to cure your lycanthropy you have to do it during a quest where Vilkas or Farkas decides that they want to cure their lycanthropy. Did you cure them already? Also if Serana has cured herself there is no way for you to become a VL. A vampire yes, but not a VL.

Yes I have already cured Vilkas etc... How do I cure my Lycanthropy and become a vampire???