Your best bet is to quit Migration Assistant at this point....Force Quit if you have to. It's possible the migration is complete and your iMac just didn't update for some reason.
If it didn't, I would strongly advise you to migrate everything from your Time Machine backup drive, assuming its an up to date backup.
If you don't have a Time Machine backup, then connect the two Macs together (via either Firewire or Ethernet) and migrate everything that way.
Migrating via WiFi is very slow, not all that foolproof, and should only be used if no other options are available.
Here's a fantastic resource for help on this subject:
Thanks, I was abe to restart but the Migration Assitant will no longer function, it keeps telling me the other computer has given up, or something like that. In any case, I gave up and am currently re-installing everything, it's taking more time than I wanted but I need to work not spend my entire weekend trying to get some software to work.