If you run a recovery scan immediately after deleting the files, you'll probably be able to get them back. Why? When a file is deleted, its data is not really erased. Actually, the hard drive marks the space it took up as a space that is available to be overwritten. So, as long as that doesn't happen, you can bring it back.
Kickass Undelete is a tool designed to recover all of those files that you've lost. It does this in the easiest way possible: just run the program, and hit the 'Scan' button on the main menu to scan your whole hard drive or external drive.
Once that's finished - it only takes a few seconds -, Kickass Undelete will display all of the files that it's able to save. One good thing about this program is that if you're looking for a specific file, you can filter the results by the filename or extension, and therefore find it much more quickly.