Depending on how many files have been downloaded or changed since the deletion many of the files may still be recoverable.
First off have her turn off her Macbook and stop using it altogether. Then have her bring it over and connect it to your iMac as a firewire hard drive, Target Disk Mode. You will need a firewire cable for the connection, start the Macbook while holding down the "T" key on its keyboard.
Then use a good data recovery program installed on the iMac to find recoverable files on the Macbook. I really like
Stellar Phoenix it worked well for me on a hard drive that seemed to had lost its partition information. Another one that seems to be popular around here is
Data Rescue II, though I didn't particularly care for it. Both have demos which can be downloaded, so you could see if there is much of a difference in the number of recoverable files.
On a side note she should have a good backup solution for in the future. I would recommend getting an external hard drive and using either an automatic data backup program, such as
Super Duper, or manually copying files and folders. If you want to save some money she or you could purchase some DVD+-R's and burn the data.