Q: RAW support for the SONY RX100?

Yeah, when?

Unfortunately this is a user forum, so no-one can answer that one for you.  You can use the feedback option in aperture to request it though.  More than likely it wont come until Canon or Nikon release some more DSLRs, which is usually what prompts an update.  For what it's worth you can use the Adobe DNG converter which will convert the sony .arw file into a .dng file that Aperture can read.  It is another step to your workflow but you can do it.

It just released this afternoon.  Run software update.

Shocker, lots of Nikon and Canon in there, never see Sony updates without one of the "big" two being involved.

Are you trying to import photos you already imported?  When you ran software update, did you see the update for Digital Raw, not just iphoto?  Run software update again if not.  Also, turn off 'don't import duplicates' and your RAW photos should import.  I can confirm this works with Aperture, which by proxy should work with iPhoto.

Whooomp.....there it is ...

https://support.apple.com/kb/HT5371