Eternal by Sally Lundsten

The world has run out of oil, much of the human population has died, and people are surviving in isolated communities. A family of vampires finds one such community has built up nearby, and Jacen, while covertly watching the people there, has taken a shine to Anna, and love blossoms.

Jacen’s cousin, Sophia, is angered by this as she wants him for herself and tries to interfere with a callous act. Charles desires Sophia, but she despises him, though her sister, Emily is happy to oblige Charles…
The village is completely unaware that the families are, in fact, vampires, and Jacen struggles to find the right time to tell Anna his secret, fearing he will lose her.

The two vampire elders receive word that something is bringing the wolves to England, but they do not know what. They fear the violence between the two kinds will be rekindled, and they leave to gather forces and report to their High Lord. (summary from Amazon.com)

Kindle Version: ASIN B00CKOJO60, Sally Lundsten, April 2013