I'd take her home (or to the closest hospital), and call an ambulance, and hopefully the cops as well. You know, if my cell wasn't working for some reason and there was no phone near. But if there were people I didn't know around, why leave her? Ask one of them to use their cell phone. If nobody near has one, ask them to find someone who does.
But if there is no one near, I'd take the chance of moving her, even though it could possibly fuck her up worse somehow (sometimes, moving someone is not a good thing, but I'd rather take the chance than just leave her lying there where I could hurt her as well through inaction.
And while I am female (and don't have a girlfriend), I think if I was male and had one, she would hopefully be understanding of the gravity of the situation. You don't leave someone who is possibly injured or dying, or who could possibly freeze to death because they are only covered by a blanket.
Honestly, would anyone do anything differently than that? If they did, unless it's bringing her to help of some kind, they are a douche.