Currently Being ModeratedJul 16, 2013 9:01 AM (in response to hughejd)
How large is your Aperture Library?
Basically you simply need to copy the Aperture Library.aplibrary package in your Pictures folder to your iMac.
If the library is still small, you could try to copy it using your network - Air Drop - or move it temporarily to your Public folder to copy it.
But if it has already many GB copy it to a portable external drive (formatted Mac OS X Extended) and then copy it from that drive to your iMac.