diskutil shows Macintosh HD is missing (with Recovery HD occupying the entire space)

So yesterday I managed to screw up my iMac 2012 (with Fusion Drive) by installing the Mac OS 10.2.2 update... The installation stalled and when I tried to restore from an external drive using Time Machine I somehow managed to corrupt my hard drive... When I try to reinstall OS X it says I don't have any disks to install it to.

Anyways, now I'm running Disk utility on the command line at boot and I see the Macintosh HD volume has disappeared. Here are the screenshots:

It seems that the Recovery HD disk is occupying the entire disk space (3TB). How do I restore Macintosh HD with a new partition so I can finally reinstall OS X?

Any help would be greatly appreciated...