I cannot relate to being that big exactly.
That said I used Myfitnesspal for intake, and I pretty much rode the bike EVERY day, if you do those two things I think your life will change a LOT, I logged around 3lbs a week loss from 304 down to the 200 range, so you could drop a LOT between now and January 1 :-).
I would encourage you to set a 90 day, 6 month, and January 1 goal, and I would think you will beat them :-).
Start a thread on your progress, come on in here and fill a water bottle or coffee cup, grab a seat and keep us posted on how your doing :-),we have a long standing reputation for success here, and your welcome to add to it :-).
EDIT: The other opinion I will share, is do not eat back ANY exercise calories to begin with....I never did and I did not die :-)......finding the exact burn number can be tough, let your weight loss show you how many calories you burned :-).