I'm willing to stay with the original concept, primarily because "a remorseful vampire" suggests it's a fable about redemption. (And I'm a sucker for redemption stories.)
But I'm uncertain as to what the operative rules are in this imagined world. Does the premise entail a rule that vampire women can reproduce? And if so, wouldn't that entail that her son would be a vampire also?
Or did she become a vampire after her son was born? Now she's trying to save herself so she can be a normal mother again. Is that what "for the sake of her son" means?
Is the ruthless hunter the antagonist? What about the villainous vampire who infected her? Or did she volunteer, the vampire who gave her the fatal bite was only facilitating her own reckless decision? Does "remorseful" means she regrets her choice?