I remember the first time I went winter camping. It was one of the most miserable self inflicted experiences of my life. I was freezing the whole time. Especially at night. I've gone since then and have had much better experiences after learning a thing or two, mainly on keeping warm. Maybe you know all the things I'm going to mention, but they were the small things that made a difference for me.
You mentioned getting a warm sleeping bag. YES. The ones with goose down are excellent. While sleeping in one of those you may wake up sweating, lol. And remember, when it comes to the amount of clothing you wear in a good sleeping bag, less is more. The special stuff in those sleeping bags can't work its magic if your clothing is catching all of your body heat.
There's nothing worse then your extremities getting cold. I have poor circulation so my feet and hands get painfully cold. I use the $1.00 heat packs from walmart to put inside my boots. They also have hand ones.
Is there a water source where you will be? If so, i'd say to heck with hauling in enough water to last you a week. For me, it was a great investment to buy a water purifier. You can either use a filter, or you could use one of those zapper things where you stick a little electrode thing in the water, and it zaps all the bad stuff. It can do something like a quart in 20 seconds. It's pretty nifty.
I invested in a really good thermos that keeps liquids warm for hours. I heat water in the morning over the fire and pour it in my thermos so I could sip on hot tea to help warm me up throughout the morning.
Best of luck! I hope your experience is everything you are seeking. :)