Working with ARW in photoshop

I purchased a NEX-C3 last November and have to say I'm delighted with it.
I was wondering though what do I need to start working with ARW in photoshop?

I currently have a mac with PS CS3 on it, and I'm currently using Aperture for basic management and processing. but would like to use PS to try and learn a few more in-depth techniques but am having trouble getting the ARW files into photoshop, i know RAW formats are not a set standard but, I can't workout if I need a plugin or need to convert them, or do I need to upgrade to a newer version?

I could google this but thought I would ask people are likely to be using a similar workflow to me!