We have tried Boomerang but it does not find the deleted file. The file was deleted 3 days ago. I would think it is recoverable, but Boomerang does not show it.
Any help would be appreciated.
PhotoRec is the best tool I've found for recovering files. It does have some baffling limitations however, like the fact that it can't recover .dmg files. It's a command line program but still very easy to use. And it's free :)
This step-by-step guide on their wiki makes it even easier.