Move her inside. Get a dog crate ready or some other sort of secure thing to keep her in, even if it is just a bath tub. If you need to, wrap her in a towel as you are bringing her in so that she can't escape.
Take her out of the coop and inside. Put her in a dog crate with towels or pine shavings for bedding, or something similar. Make sure she stays warm. Try scrambling some egg and feeding it to her. Also try making a wet mash out of chicken food. If she won't eat it from a dish, try putting it...
Is she able to walk? Is she eating? Drinking? Can she stand? Is she lethargic? Is she acting normal? If no, how is she acting and what is abnormal? Is she pooping? Does her poop look normal? Any other injuries? Is she still laying eggs? Is there any blood? Keep her in a warm place. If there is...