Get a bitfenix phenom m or prodigy m case and go mATX. You will have far better motherboard options and still a real small system. The other bonus is you can have a discrete sound card if that matters to you.
My secondary rig has the following
Bitfenix Phenom M Case
Seasonic S12G 550 PSU
i3 4130
MSI B85M Eco
8GB Corsair Vengeance
Deepcool Gammaxx 400 cooler (got it cheap - real cheap - its better than stock but nothing to write home about)
Asus Radeon 7970 GHz edition (moved from main rig which now has a 980ti)
Asus Xonar DX
Sandisk X210 256GB SSD
Two 500gig hard drives (left overs from other machines)
All of it will fit in your budget barring the GPU - you probably need to get a cheaper graphics card.