I have a newer Lenovo laptop with a factory Windows 7 installation in partition a and Ubuntu 12.10 installed from ISO in partition b. The dual boot manager came from the Ubuntu installation and there is lots of remaining disk space.

I'd like to add Windows 8 to the boot menu, or failing that I'd like to upgrade my existing Windows 7 installation to Windows 8 while preserving the Windows / Ubuntu dual boot.

Any suggestions on how to proceed?