Partiton Magic "should" do what you want, it does work with ext3 not just ext2. Ive used it before to resize & move linux partitions with out any problems, so you should be fine.

Windows 10 isn’t the only (kind of) free operating system you can install on your computer. Linux can run from just a USB drive without modifying your existing system, but you’ll want to install it on ...

Before you can partition your disk you'll need to squeeze your Windows partition to free up some disk space for the new partition. Head to the Disk Management tool, and right-click your main partition ...