If I understand correctly, the Aperture Trial will not import any iPhoto library. Since you apparently imported all of your iPhoto library into the Aperture trial, it's in the library named "Aperture trial". This library will not change if you upgrade to full aperture. You can rename it to "Aperture library", and then point Aperture to it when you next start it.
Aperture 3 (not trial) can upgrade an Aperture 2 library into its own format. This library is named (by default) Aperture Library. If you only have the AP3 trial, it's default name is "Aperture Trial Library".