You can get an ISO file from here: http://downloads.tomsguide.com/MiniTool-Partition-Wizard-Bootable-CD,0301-51034.html
Once you have this, you have a choice of media to create:
1) If you can boot from CD, download and install ImgBurn and use the Write Image to Disk option to create a bootable CD.
2) If you can boot from USB, download and install RUFUS and use the option to create a bootable USB stick from the ISO file.
Boot your PC with the media you created. You should now be able to do partition changes without problems.
Good Luck