Currently Being ModeratedSep 25, 2012 5:57 AM (in response to montenovo)
Do you still have the old Mac? If you launch Aperture there, you see the serial number in the "About" panel:
Aperture's main menu bar > Aperture > About Aperture.
The serial numbers are on the box/booklet of the packaging that came with the installation media or in an email, if you bought online.
If you cannot find them, contact Apple with a proof of purchase: