Good news is your windows files should all be there. You've destroyed the windows boot sector by installing grub over it. You've also replaced the windows bootloader in the MBR.
So, if you can get a live USB going, you can fix the bootsector with testdisk. And you can install the lilo bootloader (matches windows functionality in the form shown below). See this link for instructions for the boot sector fix: http://sourceforge.net/apps/mediawik...ms:Boot_Sector
To replace the bootloader run:
If you can't boot ubuntu then you need a windows repair disk. And you need to run
sudo apt-get install lilo
sudo lilo -M /dev/sda mbr