Per the specs, you will need an ATX case. Get a mid tower if you like it to be compact (full tower is bigger).
If you are going this route I suggest that you take out the motherboard along with as much components as possible and then transfer component by component into the new case as sub-assemblies as much as possible.
Here after, u'll need to disconnect wires & even use screwdrivers for some components:
Take the drives out.
Take the heatsink/fan(s) out.
Take the Power supply out,
Take the Motherboard out (then compare the screws' layout with the one on ur other chassis... some Dell models like Optiplex have a different layout, they won't fit in any ATX chassis unless u mod the later, I don't think this one's like that, but u better make sure)
Don't take the CPU out of its socket for any reason. U better leave it in all of the time. U might want to clean it out & change thermal grease though.
Intall Power supply first, then MB, coolers, drives, cards, RAM & plug things in... Enjoy!