Hiya
ooohhh lucky you.. we're not going this year, am really regretting it now!
As others have said - layers are they key.
A good thermal base layer with wicking properties - that means the material takes the moisture away from your body - stops you getting a chill when your sweat cools, a long or short sleeve t-shirt - depending on the temperature/how well you are coping with the cold, a sweatshirt and a decent waterproof/windproof/warm coat.
Your usual coat will NOT do - you should invest in a good coat. You will be miserable if you get cold.
If it is really cold i wear a pair of silk gloves under my skigoves. You will need these as wooly gloves will not stop the wind getting to your hands.
You can buy all you need at TK MAXX - you do not need to spend a forture. We are on our 6th trip and still using stuff from our first, if you like your week you can always change/upgrade your stuff as you go along.
If you are into snowboarding you can buy padded goalkeepr type shorts to prevent too many bruises!!!
My top tip would be to get in the jacuzzi on your return after your days skiing.. it really eases those tired legs!
Dont overdo the evening entertainment... it might spoil your daytime, and after all that is what you've gone to do.
Have a fab time.. i'm sure it wont be your last!!
KAtie