How do you know how much you need? What if it's going to be the coldest winter ever?
I usually have about 10-20% of the total I have right about this time before I start burning it for the winter left for the following year. I don't just get enough to last exactly as long as I need. That insures that if the winter is long I will still have some left and have more room for error, and it makes it so I can start off the winter burning the dryer wood if the newer wood needs to dry out on the stack a little.
One of the things about burning wood for heat though is that unlike burning gas or fuel oil there is only so much one can do to adjust it rate it burns. There are dampers and air intakes that can be finessed to slow or speak up how much it burns or how hot it is, but in a lot of respects the fire is either burning or it's not so even if it's really cold out I still generally get the amount of heat from it I would any other time and it will just be colder in the house. If it's already burning good there isn't too much more I can do to just turn it up any more after that like people can with a thermostat with a conventional heating method.
By the way, I noticed you have a Lions signature. Are you turning away from the Jets?