hello...is possible have a Christmas card of c2 optimized for facebook cover ?

If you can tell me what you need I will be happy to try. If you are looking for an image with your message on it then I would suggest downloading and installing greenshot on your computer and sending the card to your email address. Then you can take a snapshot of the card (timing might take a few goes with the anination) and upload it.
As far as I know you can only upload a photo for your cover, whereas the Card is animated html5, so the only option is to use greenshot or similar to convert it to an image.