Would suggest you install Partition Wizard HERE. Free and outstanding.
Then you can resize the partitions to suit.
Or create a partition to the required size for either OS and clone to this custom partition.
If you only want to copy/clone data files to the new partition,the easiest way might be to clone the whole lot-remove everything which isnt needed (Windows and Program Files etc- one simple delete each).All this should be achieved in 5-10 minutes as long as the system isnt active of course.
Then work on the Doc and Settings Folder to extract the required data files,also painless, as all will be in folders.
You can also slide the partitions around in a dummy run,to see whether everything will be feasible.
The dummy resize isn't activated until you press 'Apply".
Presumably you are already using a Boot Manager.