I'm pretty sure the reason why your computer isn't recognizing our camcorder is because of this. Your camcorder has a specific files system which iMovie / Final Cut will recognizes. Just importing .MTS files into your NLE will probably not work. What you could try doing is formating your memory stick using your camcorder, then record some test footage (only one clip should do, then connect your camcorder to your mac and open it in finder (it should mount like a flash drive / external drive). Once here look at the file structure and locate where the .MTS files are stored. Once you know where the files are stored, you can go back to your PS3 and copy all of your videos (.mts) to that specific location and try logging and transferring again.
Why even bother dealing with iMovie when everything can be done with far more control in final cut?
BTW you don't need a 8 core mac pro just to edit with AVCHD. I get by just fine with my MBP.