The Windows Disk Management Utility is suitable for resizing and creating partitions. I would think it is part of Windows 7 Home Basic.
To find it, click on "Start" and right click on "Computer" then "Manage". You may be asked to confirm a UAC prompt.
Click on the "Disk Management" section.
If you right-click on the partition you want to shrink (here I've got two partitions, typicall you'll have one) and then choose "Shrink". You will only be able to decrease the amount of space you have free on the drive. Once you have done this, Right-click in the new space (black) and create a new partiion there.
If this does not work or you have difficulty, try a GParted Live CD, or the GParted utitlity in a Ubuntu Live CD