I snowmobile in the mountains, so have good gear for that that I can wear her in MN for other things. I use the "old" stuff, and save my newer high end stuff exclusively for sledding. But my next in line stuff is by a company called RU Outside. I have their underlayer stuff and boots and LOVE them.
Here in MPLS we have a winter parade called the Holidazzle, and my niece and her stepdaughter were in it last weekend. about 12* with wind...BRRRR!
I had the heavier underlayer on (like snug sweatpants) with thin loungepants/sweats over them and my legs were toasty, along with the RU outside boots (they have the felt liners so I never wear socks with them, ever. I hate sock-snuggies!
You need good layers like this. Underlayer, then a shell or windpant type outer layer would work, an underlayer shirt, perhaps a fleece top and a good jacket. Tuck things in and avoid cold air gaps. Mitts, a neck gator and a hat. Fleece is great for these pieces. AVOID COTTON! When we ride in the mountains, there is a general rule and saying...."Cotton Kills". We don't wear any cotton at all (not even in undergarments). Thats why fleece is great...its polyester.
Just because something is many layered does not mean it is warm. Look for something made for snow sports, micro layered warmth, etc. Do some homework on that if you plan to spend some money on your items. I get many many years of hard use out of my sledding gear. Don't wash with fabric softeners and dryer sheets (apparently this reduces or breaks down some of the products they use to weather proof the fabrics?? Thats what we were told at some of the conventions by different companies).
Links to good companies in case you are interested in some good gear!
BTW~ What kind of 157# fur baby do you have? I used to have a 160# Newfie...miss him everyday, especially when it is snowy!
http://www.ruoutside.com/
http://www.klimusa.com/catalog/Snow,2.htm