Well if you cannot get hold of a Fedora disk, you can do without it. Boot into any live cd that supports your hardware and filesystem used (
AFAIK fedora uses ext2 or ext3, so this should not be a problem), mount the partition which contains /boot, on a directory, if the hard disk is hda1, use
Code:
mkdir /mnt/fedora
mount /dev/hda1 /mnt/fedora
chroot to /mnt/fedora and proceed as gaurav explained.