1) Release Drives from connected vm and Run as administrator. (note location)
2) With cmd line navigate to location of Oracle VirtualBox drive tools.
3) Clone VM using cmd line: vboxmanage clonehd, Options --format VDI --variant Standard
4) Run VBoxManage modifyhd cmd with --resize otpion.
5) Restart Virtualbox, Add the new resized VM to the previous VM. (or make new one).
6) In Operating System extend the partition to use the full disk space.