Get some REALLY good boots, they are one of the most important parts of your gear. I would recommend these;
http://www.cabelas.com/cabelas/en/t...parentType=index&indexId=cat601929&hasJS=true - boots
and these
http://www.cabelas.com/cabelas/en/t...parentType=index&indexId=cat600967&hasJS=true - socks
Get some good gloves - I would recommend getting the below
and some of the wool mil-spec type style liner gloves. Between the two, your hands should be toasty. Cabela's might have some good choices too.
http://www.sportsmansguide.com/net/cb/cb.aspx?a=110998 - Goretex insulated mil surp cold weather gloves.
Top it all off with a good thermal, sweater, coat, gore-tex shell and you are set. Layering is the cheapest option. More expensive is buying an ALL in ONE jacket from Cabela's or the like.
Sportsmansguide.com and armysurplusworld.com have good prices on MIL-Surp stuff. I don't know how cold it gets where you are, but I am pretty certain that they have surplus you can pickup cheap that will work in it fine.
I purchased this the other day -
http://www.sportsmansguide.com/net/cb/cb.aspx?a=59123 I wouldn't wear it on a date, as it looks bulky and long, but in the field, I don't imagine you would get cold. In combo with a poncho, doubt you would get wet either. You might want to try it or something else. ONE FREE HINT about buying cold weather stuff from sportsmansguide, if you purchase say a German Parka - you might want to call or read the comments or carefully read the description as they do not all come with liners and you basically end up with a canvas type jacket with a liner that is MIA and not easy to find. You can of course use a fleece or something else under it, but I like to have it configured the way it was designed to be.
Good luck.
EDIT:
Liner socks also...
Forgot to mention that. Put a pair of liner socks on, then wool socks, then the big boots and you are set.
Some boots come a little large others you need to order 1/2 size larger to compensate for your feet swelling and the added bulk of the sock. That is one reason to stick with order the boots from Cabela's as they have really snappy return policies and YOU DO NOT want to skimp on your feet.