Verified answer

You have an ATX/MicroATX board, so search for a larger case which accepts those types of boards, specifically MicroATX to guarantee a fit. The power supply is a 550 watt supply, and will fit pretty much any case you find, but if you are looking to upgrade you are going to need a larger case, most slim and micro cases won't fit much more than a 550W, even though I've seen 800W+ in them, this causes heat issues and can burn out the power supply or cause it to shut down randomly if it has a thermal safety unit installed.

If it's an ATX mobo don't try fitting it in a μATX case! If it's a μATX mobo it'll fit in an ATX case. 550W means 550 watt.

if you go on ebay you will find cases that are excatly what you want and yes, it does mean watt