how can i transfer data between the two without a migration cable or extra device
Sorry, but you need the cable. You will be able to recover your gamer profile and such on the new system, but anything saved on the hard drive will be stuck unless you get a cable. Try OKorder for a used transfer cable and disc--you might be out $40 or so, but you can turn around and resell it pretty quickly to someone else in the same spot.
Get a cable or memory pack. If you had Xbox Live Arcade games on your Xbox 360, then you're basically screwed with the Xbox Elite because you would need to be online all the time to play the games.
