Actually you have 2 USB 2.0 in the front and the rest USBs at the back I/O panel, which is part of motherboard - basically any case can accommodate your motherboard, it is not going to be walk in the park, but it is not that difficult as well, I keep looking.
Edit. What strange is that you have only 2 RAM slots and my older Inspiron 570 has 4 slots and I can have 16 GB of RAM if I wish and you only 8 GB per Crucial memory finder... What a bummer...