Trouble With Extruded Cut

[Frozen Jamaican]

Hello everybody! I'm new to modeling in Solidworks, so I don't now the best way to do this for my project.

I'm trying to make an Xbox Original case that's as close as possible to the original, and one of the problems I'm dealing with is cutting out some of the material out of this box. All I need to do is curve the top and bottom, like in this image. That's the hardest problem I've dealt with so far. If you know how to do this please let me know, it'd be very appreciated! Any criticism is also welcome.

Here's a link to the case as it is. https://mega.co.nz/#!3g0GXY7I!id4mFtCVudzS-Dz5iEZp6Wgeimxk__Ayd0leu_BMOro
I've also attached the dimensions for the case as well.

 

[rhariz21]

how did you model it? if you extruded it from the top plane, you would simply change the top and bottom lines to arcs