I really don't want to buy anymore fans, at least not right now.
For conversation's sake, using only the fans that come with the case (2x120mm), how should I arrange them to get the best air flow? Original orientation is one intake in front and one exhaust in back.
I'm using the Hyper 212 EVO and a Sapphire Nitro R9 380, just to give you an idea of what other fans are in the case.
Yep, one fan in the lower front (if the front is dual fan) and one in the exhaust. it does not look like you have many options with that case, maybe some side fans and one in the floor. (I can't tell from that profile pic) But with only two fans, Your stuff is limited. I can tell you right now with your GPU, as I have the same one, you will want more case cooling.