James87,
To be brutally honest, Yes, you are fighting a loosing battle. I know. I'm right there with you.
Its easy to say walk away, not so easy to do, I know.
I am afraid that until or if the veil of JW is lifted from you're GF by her own hand, there is not a damn thing you can do. Do you wait? Or walk? Who knows. Only you can make the decision. The more you fight, the harder the battle. I know.
I am assuming that she has been told not to 'associate' with you. So in her mind she is fighting a battle of her own. The constant flip flopping is wearing and so frustrating, you think you're getting somewhere, then WHAM! The guilt kicks in.
My way? For now, I wait. I listen. I talk. I'm there. I am the bad association.
I have no advice for you because I am in a similar situation. But I send my best wishes. Love is a funny funny thing.