Hi,
I am not quite sure about your libraries - please clarify:
I currently have an iPhoto library in Aperture. It has some iPhoto pictures in it, but not all of them.
What do you mean by "an iPhoto library in Aperture"? Have you imported from an iPhoto library to Aperture?
My question is what happen in regards to iPhoto pictures once I update Aperture. I understand iphoto pictures will be available from with in Aperture somehow, but will I still need my iPhoto Library or should I delete it and then just have all of iPhoto in on place?
iPhoto pictures you already imported to Aperture will still be available, since they now are part of your Aperture library.
But Aperture will not automatically import your other iPhoto Libraries, unless you do that. However, you can open, browse, and edit any iPhoto Library using Aperture, and you can use iPhoto to work with your aperture Libraries. So it may not be necessary to import the iPhoto Libraries into your Aperture Library, unless you want to have one consolidated library.
Here are some Support articles, that might be helpful:
Aperture 3.3: Using a unified photo library with iPhoto and Aperture
iPhoto '11: Use iPhoto with Aperture
Aperture 3.3: How to use Aperture to merge iPhoto libraries
Regards
Léonie