there are programs out there for data recovery but they all suggest (wisely) that you use a different disk to restore to, have you got an external hard drive or similar ?
most important I hope you are not using that machine ATM, the more you use the machine the more you reduce your chances of a successful recovery.
if you have a backup drive and have not used the PC much then look for and download a linux live cd such as this
, then google for 'testdisk' and 'photorec', bith of which (actually the same program) are on the live linux.
if you get stuck , post, just NOT on the affected computer!