you'll probably get the best deal on everything at sierratradingpost.com one order, one shipping charge no sales tax and with use google pay to get $10 off. Here are some quick finds I came up with.
Balaclava $6.36
Tights $11.96
I didn't immediately find any shoe covers there though. youm might consider goretex sealskinz or similar waterproof socks. I think nashbar has a windproof sock. Might be cheaper than a shoe cover and work just as well ...