Stop using your computer. Download (preferably on another computer) Restoration
http://www.majorgeeks.com/Restoration_d4474.ht ml (sorry - can't check link from work). Stick it on a USB drive and put that in your computer. Run the program from the drive (no need to install) and scan any relevant drives (probably just your C: drive). This may take some time if you have a large drive! Save any files that you need to the USB drive.
This may work, but only if the data hasn't been overwritten too many times. If you did actually
erase the data rather than just delete it from the bin, it probably won't work.