I bought the Oblivion GOTY version for my Xbox 360 Slim...and it won't let me install the dlcs from the second disc. It says I need an official Xbox hard drive(my 360 is official, I got it at Best Buy and its the 4 Gig model(2 gigs of space left and a USB drive with 5 gigs of space left) to install the dlc and then returns me to the 360 home page. I don't have the money to buy a $100 larger hard drive for my slim and I don't want to buy an unofficial one so buying more memory isn't an option.

My question is, how can I play my dlcs?