Have a backup of all of your partitions before you make changes here. Errors that might arise with repartitioning can lead to data loss in some or all partitions.
Use a virtual machine? Parallels or Fusion are the two common choices. The VM avoids the need for rebooting, and provides flexibility around disk images, rather than disk partitions.
Older Windows partitioning used MBR partitioning, and there are four partitions available in the MBR. GPT (GUID) partitioning has many more partition slots available. It's likely your OS X system is already using GPT partitioning, too; that's typical with most OS X systems. GPT Partitioning Background: Apple Secrets of the GPT (TN2166).
Usual tools for shuffling partitions and for setting up for Boot Camp are Boot Camp Assistant and also see Two Canoes (source of WinClone) has a write-up for working with larger drives, and (in general) you cannot use Fusion Drives (HT5446) here. But in general, a VM will probably be easiest.