Recover files emptied from trash bin?

Some specialized data recovery programs can do it if you didn't securely emnpty the trash. When you do a normal erase, it doesn't wipe the files, just returns the space and marks the filename as free.

 

Google for "Data Rescue 2"

 

Also, if it's not already too late, stop using that machine. The more you use the computer after a delete, the more likely it is that the former HD space for that file will get overwritten and thus make recovery increasingly difficult. I've never had a ton of luck with recovery software, but still worth a try.