Well I came up with these two parts as possible replacements for the motherboard and power supply. Also, as I already said, I would recommend going for the GTX 970 and just double check whatever GPU you choose will fit the case since it is a smaller case.
PCPartPicker part list:
http://pcpartpicker.com/p/zfLBFT
Price breakdown by merchant: http://pcpartpicker.com/p/zfLBFT/by_merchant/
Motherboard: ASRock B85M-ITX Mini ITX LGA1150 Motherboard ($77.98 @ Newegg)
Power Supply: SeaSonic 620W 80+ Bronze Certified Fully-Modular ATX Power Supply ($78.98 @ SuperBiiz)
Total: $156.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-09-20 12:33 EDT-0400
I went with a fully modular PSU since you have a smaller case. It will support most GPUs...but please note that it only has 1 6 pin connector and 1 6+2 pin connector for PCIE connections. The newer 970 980 series GPUs I think use 2 6 pin connectors...so it should be fine with that.
As always you need to compare the features of those components to the ones you already selected to see if they still meet whatever wants and needs you have for them. But overall if you ended up choosing them as replacements, you would end up saving around $93...which could go towards improving the GPU or getting a HDD.