Don't even think about wearing skirts. You need the 'onion' layering technique - a pair of decent thick tights beneath a pair of thick trousers (eg made of a woolly material, or cords, or thick jeans - you can probably use the same ones suitable for a GB winter). Then at least one extra pair of winter socks over the tights.
The boots should not be normal fashion boots - the sole will be too thin for that temperature. Best of all is a thick, flat sole plus a fleecy lining, and they should go at least over your ankles. TBH once the temp goes down that low I often wear my winter walking (trekking) boots, with ice cleats on icy days.
On top, layers is the key. A t-shirt/long-sleeved top, then a thick jumper or fleece, and a lined wool coat on top. Whether the coat is short or long is a matter of personal preference. I find really long coats tend to sweep apart anyway on windy days, leaving your lower legs exposed however hard you try to keep the coat together (unless it really buttons all the way down). I currently have one very short, hip-length coat, one knee length coat, and one very long one, which I can only wear on non-windy days.
Bonsoir is right about the need for good accessories - hat, scarf, gloves should be your mantra. Never leave home without any of them, and you can never have too many of them. The hat should cover the ears - some people do fine with a woollen headband instead. The gloves don't have to be sheepskin, but should certainly be as thick as possible. If you're doing sports (that includes riding a bike and snowball fights) the artificial fibre skiing-type ones are best.