Can I import a song from itunes without having to drag it out of itunes onto the desktop first?
There should be a folder that iTunes keeps your actual .mp3 files in. You can navigate to that folder and select the appropriate audio file from within that folder.
That's a very clunky way of doing it because (a) iTunes stores some files as AAC which don't import into Proclaim and (2) the iTunes folder structure is very hard to navigate.
Yes, that is the case. The AAC files will need to be exported at .mp3 in order to be processed by Proclaim.