So i went to the xbox live marketplace through the dashboard and redeemed the code given to me. The 108 KB File downloaded. Now what do i need to do to export the songs. Yes I realize now there was a better way to do it.
The 108 KB file is called the LEGO Rockband export pack.
I've also tried going to the LEGO RB Music Store > Export Songs > Redeem code... but ive already used the code so that doesnt work