If I am going to make 400 hats I am going to need some more yarn, Right?

After moving 6 times in 2 years my yarn stash had become quite depleted, Several times i went through it and gave alot away, but after deciding to go in the 400 hat exercise  I realized I was going to need more yarn... I know this isn't nearly enough to do 400 hats, but it is a start. I figure every month I will get some more and all will be well. The black yarn is already mostly used up on a manly style hat for my Lovie.  I think i want to make myself a pumpkin hat with the orange, it is October after all.