How to recover erased Mac files? PLEASE HELP!!?

I accidently erased all my files, documents, media, ITunes, info, etc. by reinstalling the Macs OS X Install Disc. Unsure how to recover all lost data. How do you transfer old volumes? I would REALLY appreciate the help.
I accidently erased all my files, documents, media, ITunes, info, etc. by reinstalling the Macs OS X Install Disc. Unsure how to recover all lost data. How do you transfer old volumes? I’ve been looking around the web and ‘Mac emergency hardware recovery’ keeps coming up. WOuld that fix my problem? Know any safe free ones? Thank you.

You will need to buy a recovery program to recover it all. its alot harder to get stuff back on MAC than Windows.