What would my best option for improvement be for around the $500 range? If I decide to get more GPU's, I would have to get a new motherboard as I currently have the MSI B130 gaming edition which CANNOT support more than 3 GPU. I could potentially get an asic though... I do not really know much about which ones to buy or value, however I do know how they work.
with your current improvement cost, adding more GPU to your rig were the best thing that you can do.
You were using MSI B130 gaming edition, from what I saw on Google image, this series, whichever version had four PCIe socket (2 x PCIe 1x - 2 x PCIe 16x). But I'm not sure since you said only three cards could add.
With $500 may you can add one or max two 1060 6Gb, so your current board has good enough for handling all of your cards at this moment. You don't need to add another thing besides GPUs.
I currently have an EVEGA 1000w PSU AND an EVEGA 600W psu. Would it be possible to rig them both up? Not sure how that works. The 1000w is currently connected to my gaming rig.
At this time those 1000 Watt was enough to handle your rig, even when you ad one or two more cards. But you can combine those two with some tools (as above said) or some technique (such as paper clip jump-start).
