Welcome to the forums.
You screen shot is not showing any LInux partitions. It that supposed to show your install? Are you sure it is not wubi then?
You can shrink the Windows partition and move extended left into the unallocated. Then inside the extended you can make as many partitions as you want. You would have to unmount the extended. The little key icon says it is mounted.
If you want to shrink Windows use the Windows tools to shrink it and reboot several times, so it can run chkdsk and update to its new size. But do not create partitions with Windows. Use gparted or the installer to create new partitions.