Your making this too hard on yourself download and burn the iso and boot the PC with the CD in. When the time comes SUSE will let you choose your partitioning yourself or automatically while not touching your Windows Partition. If there is no free space use Gparted an exact working clone of Partition Magic.
That is all no extra unessesary steps in the past it was different when you had to do it yourself but like anything it's now automatic and more user friendly.
