I was just abroad in a very cold part of the world - fortunately I was in a low-income country so everything was affordable at the bazar. Finland will not be too bad actually, since they have money you will be in heated buildings most of the time. Something to consider is - will you be walking a lot? If so, you will need warmer clothes. If you will have a car or be on heated transportation most of the time, it won't be so bad. They will have plenty of things to buy there, it might be tough to purchase things in Texas. But the things there may be expensive - you might want to check what would be cheaper, buying things here are there. Also, brining warm stuff takes up a lot more room in your suitcase. If you buy things here and there isn't much in your area, sporting good/outdoor stores like REI are great if you can get sales.
Things you will need:
Down or fur coat with very good hat, scarf and gloves
Lined boots (fur or fake work)
Long underwear (multiple types to layer, i.e. a thin pair like silk and a thick pair like fleece)
Thick wool socks/knee socks
Wool sweaters and fleece (also multiple thicknesses so that you can layer on two sweaters or two fleece on top of a long underwear shirt)
If you are cold inside make your sure have a beanie hat on, thick warm socks, and get fingerless gloves (preferably wool and fleece lined) so that you can do things like type with them on. Also, drink lots of tea or hot liquid. If you have a good thermos that helps.
Enjoy the experience!