Bootcamp Partition question....

Hey all, I have myself Win7 installed via Bootcamp, with all recent updates installed. When I first granted 100GB to my 500GB HDD, I thought it would be sufficient enough. Now, I have a few games installed such as BF3, MXsim, Skyrim, etc. I only have about 25GB left, and im wanting to make it bigger.

So, how would I go about adding space to the Win7 partition? Would I have to erase BOTH OSX & Win7 partitions? I really hope not....

Any help would be appreicated!