Patience, Ploppy. People come here to offer advice when they can.
I know that the latest version of iMovie, iMovie10, will import Projects and Events from the previous version, iMovie v9(also known as iMovie11). I don't know if it will do that with iMovie 8.
So, just copy the iMovie folders from your external drive into the Movies Folder inside your Home Folder on your new Mac. Run the latest iMovie on the new Mac. If it can import your old iMovie stuff, it will ask you. If it doesn't, then it can't.
Did you not use Migration Assistant to move all your stuff from the old Mac to the new one?