Windows lacs the ability to allocate and partition disk space like a mac. In order to add space to the drive you are using on windows, you must back up your windows partition to an external drive, delete the partition and create a bigger one. I would recomend a program such as Parallels Desktop 7 for mac wich allows you to run Mac and Windows at the same time as well as using the same disk partition. Therefore, nor rebooting, and no running out of windows partition space. It is literally running windows like an application inside of Mac OS X. I have the program, and I am very pleased with it. You can set how many CPU cores and Ram the Windows partition is even allowed to use. Also, Coherence mode allows you to run the two system together. See Below.
