Has anything been written to the disk since the deletion? If so, your file's probably toast.
As I understand it, (Any file system Gurus out there...Please correct me if my concept is wrong) the inodes are what is used to point to the various file "blocks" which make up the file. Like the arrows below.
Data Block --> Data block --> Data Block --> Data block... etc.
All the blocks together form the file. When you delete the file you loose the connection between the blocks. If you've saved any other file the inodes may have been re-assigned, original file blocks overwritten, and the original file's gone.
I'd be interested to see what others say though.