run your partitioning tool (my example uses partition magic).
your windows drive will look similar to:
now click this image and from the left hand menu select create a new partition
: click next twice. Then make sure the new partition will be created after
the current partition, and click next again.
click next once more then you will get to choose the size of this partition. Based on the amount of data you need to save it will likely be a few gigs (NOTE 1024MB=1GB)
Name the drive, then click next.
you will now have a second image resembling:
then to the bottom left click apply
. This will restart your computer, upon restart partition magic will do it's thing separating your drive.
It will then likely restart again, and load into Windows.