I can share a life-changing secret with you - cold legs can be a thing of the past!
For years I have run in the mountains near the Cairngorms and in the winter after most runs when I came home, if my legs weren't actually numb then they were bright red and sore.
Last Christmas my lovely hubby gave me Mountain Equipment Powerstretch tights. Bless him! I now look forward to taking on the elements. I could say that Ileap and bound gracefully across the hills like a gazelle in tights but alas, no. I still gasp and wheeze and question my sanity but now it's with a warm bum and legs. I've run recently in a blizzard in these and they are the business.
Incidentally, he bought me Sealskinz waterproof gloves and a Montane extreme lightweight jacket too and they have made such a difference. The only problem now with winter running is me!
Hope this helps, even though it's a bit late ...