Hmmm, you are rapidly running out of options. Here are the ones you have left:
1) Find an install disc that you can boot off of.
2) This is a friend's Mac, right? And you also have one? Turn their computer off. Get a firewire cable (same 6 pin male connectors on both sides) and connect the two computers together. While connected, boot their computer holding the "T" key down on the keyboard. You should get a different onscreen icon (of a disk). After this, you should see their Mac's hard drive mounted on your desktop. You can then try to repair the disk from your Mac.