I have a basic set of Wall's insulated camo coveralls. You can also get them in bibs and a jacket. The insulated coveralls are really great and warm. I mean WARM! I wore a pair of thermal long johns and thermal T-shirt, then a pair of sweat pants and sweat shirt, then finally the insulated camo coveralls. I ROASTED MY A$$ OFF!!! And this was even on a cold morning in Virginia when it was 18* outside and 2" of snow/sleet.

The insulated camo coveralls are awesome and allow for good mobility and are, uh, really warm.... I would look at getting something like that.