You could plug your iPad into your iMac via USB and transfer them with iTunes. You could also copy the files via USB through Finder from your iMac to your iPad though that may be a little more complicated.
Honestly I am not completely sure, because I have never done it myself. I don't want to give you inaccurate information. Is there no way you can do it with iTunes? If not, have you tried contacting Apple support for the problem with AirPort?
