OK, so from your motherboard specs you're running USB 2.0 and you've got 4 external USB ports, and if your mouse is on one and your keyboard another, then you probably have 2 left,unless you have a printer on one. So you do have an external USB 2.0 port to run the Mediasonic box Kilroy mentioned (it looks good) even though it will take USB 3, you don't have that, so your data will just move slower (according to user reviews it is backwards compatible with USB 2.0 - not all hardware is since USB 3 provides more power than USB2, but this is specified to work fine with USB 2.0). But, you do have internal sata on your motherboard (4 sata ports in fact, though I don't know how many are still available, and you have pci-e slots as well.)
So basically the easiest way is to get the Mediasonic box, plug in your hard drives, and plug it into your available USB port. You could move data slightly faster by using the esata option on the Mediasonic box, but that would mean you would need an esata connector to plug into your motherboard, unless your case has one on it (and it might). If it does, then use that, it will transfer data a little faster. (It looks like your motherboard supports SATA 1). Also the mediabox is built for 3.5" drives (standard desktop size drives), so if you have the smaller 2.5" (laptop sized) drives then you'll just need adapters to plug into them so they'll fit.
But.... if you wanted.... you should be able to also plug in a PCI-e board internally which will give you probably 4 USB adapters so you could do it that way as well. (Your case specifies a mid-size tower so it should fit fine.) If you aren't into opening the case on your computer, then the media box is the way to go, and actually is a good way anyway.