I am sorry to hear about your Doberman's injury and that the paw is swollen and now cold. My name is Rebecca. I am a veterinarian and will do my best to help.
The paw being cold really worries me. There could be reduced circulation of blood to that paw, and that could be dangerous. I would continue to rest her and limit her activity, but I wold not wrap the paw or put a splint on it. It should be checked out as soon as you can get her to a veterinarian. Can she feel her foot? Will she put any weight on it at all?
I am glad she can feel the foot, but worried about it being cold. I hope you can get her checked out soon; please let me know what you learn. Thanks for the good rating.