How can I tweak this build to make it so it can run GTA V at medium-high settings?

Solution
best i could do. its $50 more, and had to cut down to an i3, but games are more GPU dependent and the 280X is much better than 750ti

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i3-4170 3.7GHz Dual-Core Processor ($113.88 @ OutletPC)
Motherboard: MSI H81M-E34 Micro ATX LGA1150 Motherboard ($45.90 @ SuperBiiz)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1866 Memory ($36.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($40.50 @ SuperBiiz)
Video Card: XFX Radeon R9 280X 3GB Double Dissipation Video Card ($218.98 @ Newegg)
Case: Corsair SPEC-02 ATX Mid Tower Case...
best i could do. its $50 more, and had to cut down to an i3, but games are more GPU dependent and the 280X is much better than 750ti

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i3-4170 3.7GHz Dual-Core Processor ($113.88 @ OutletPC)
Motherboard: MSI H81M-E34 Micro ATX LGA1150 Motherboard ($45.90 @ SuperBiiz)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1866 Memory ($36.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($40.50 @ SuperBiiz)
Video Card: XFX Radeon R9 280X 3GB Double Dissipation Video Card ($218.98 @ Newegg)
Case: Corsair SPEC-02 ATX Mid Tower Case ($59.99 @ Amazon)
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply ($48.60 @ SuperBiiz)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.20 @ SuperBiiz)
Total: $581.04
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-10-29 23:19 EDT-0400
 
Solution
Here's my go at it.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor ($163.99 @ SuperBiiz)
Motherboard: Gigabyte GA-B85M-DS3H-A Micro ATX LGA1150 Motherboard ($49.89 @ OutletPC)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($40.50 @ SuperBiiz)
Video Card: PowerColor Radeon R9 380 4GB PCS+ Video Card ($199.99 @ Amazon)
Case: Fractal Design Core 1000 USB 3.0 MicroATX Mid Tower Case ($29.70 @ SuperBiiz)
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply ($48.60 @ SuperBiiz)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.20 @ SuperBiiz)
Total: $583.86
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-10-29 23:30 EDT-0400

If you absolutly can't go over the $530 of your build theres this.
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor ($163.99 @ SuperBiiz)
Motherboard: Gigabyte GA-B85M-DS3H-A Micro ATX LGA1150 Motherboard ($49.89 @ OutletPC)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($40.50 @ SuperBiiz)
Video Card: EVGA GeForce GTX 950 2GB Superclocked+ ACX 2.0 Video Card ($139.99 @ Amazon)
Case: Fractal Design Core 1000 USB 3.0 MicroATX Mid Tower Case ($29.70 @ SuperBiiz)
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply ($48.60 @ SuperBiiz)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.20 @ SuperBiiz)
Total: $523.86
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-10-29 23:31 EDT-0400
 


Thanks