Hi Mayasmama, I ordered the fleeces from a UK company called Equafleece, (I still haven't worked out how to copy the link but if you google it you'll find them) I'm in Germany and they dealt with my enquiry and posted to me with no problem. They tell you how to measure your dog up and then will send the right size, - they're very helpful. I have the two legged one and Humphrey can pee in that no problem, I'm pretty certain the four legged ones will be the same. They have a variety of models and colours aswell. We have the same problem with the snow but the fleece certainly helped and I'm going to get a 4 legged one this year as the back legs are the worse problem. I also keep the hair on the feet short.
Best if luck, let us know how you get on!