Help! I'm literally due to have a baby today and need to sort out video footage storage

Question

I just went to check that the battery is charged on the camera and got a notice saying the hard drive is full!.!!!!!!!!
I have previously imported the video onto our Desktop Mac ( which is currently in storage)  and think I have a back up too, but I'm worried about whether the data, once imported is usable in other formats.  Ie if we change program or operating system later. 
I have purchased an external harddrive and dropped and dragged to copy the files from the camera itself, but when done that way, can't seem to play the files directly from that drive using either Imovie or Quicktime.  My Mac Pro is full and  I need to clear some more room on the camera but I'm terrified to delete precious footage of our other baby.
I'm no techno, I know I'm using a Sony HDD camera, and IMovie 09 version 8.0.6.
HEEEEEEEEEELLLLLLLPPPPPPPPPPPPPP Please!

Answer 1

It is best to keep a copy of the entire contents of the camera. You need all the folders, even the empty ones. If you have this, you can import the footage into iMovie or Final Cut later without losing anything,
An easy way to do this is to go to your iMovie import screen. Toward the bottom, it should have an option to Create Camera Archive. This will transfer all the contents of the camera to your hard drive, and can be imported later.
If this footage is important to you, I would recommend that you also back it up to a second hard drive.
Once you have it stored and backed up, it is safe to delete the files from your camera.
To answer your other question, if you have already imported the AVCHD files to iMovie, then yes you will have them, and yes you can use them in other programs. On import, they are converted to Apple Intermediate Codec, which certainly any Apple video editing program can read. I don't know if they would be easily readable on Windows. When they are converted to Apple Intermediate Codec, they get 6 to 10 times larger than the files on the camera. This is because AVCHD is a highly compressed codec, and not suitable for editing.
So, yes, you have the AIC copy of your events in iMovie, and that is probably enough, but it is good practice to keep the raw AVCHD files. This lets you keep a copy in a compressed form, and gives you a copy that is exactly as you took it on the camera, before any processing.
I wish you the best with your new baby!