Xbox 360 - How do i save all my download content and game saves?

I have the Xbox 360 Halo package console. My console seem to had a premature death maybe because i play games 2 days in a row without rest.

Anyway i have lots of downloaded content such as:

*Gears of War Extra Maps

* Halo 3 Maps

* Forza 2 Extra tracks

* Halo 1

And not to mention that i have finished Gears of War on the hardest level and i want to keep the gamesave profile.

I like to know what options do i have if i want to save all those up above and load it to my new Xbox 360 console.