Tried to keep using your power supply since it's a nice power supply and your budget is quite limited, but the power is not really high. Came up with this:
PCPartPicker part list / Price breakdown by merchant
| Type | Item | Price |
|---|---|---|
| CPU | Intel Core i5-4460 3.2GHz Quad-Core Processor | $176.95 @ SuperBiiz |
| Motherboard | ASRock H97 Anniversary ATX LGA1150 Motherboard | $69.89 @ OutletPC |
| Memory | G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory | $54.89 @ OutletPC |
| Storage | Kingston SSDNow V300 Series 120GB 2.5" Solid State Drive | $52.89 @ OutletPC |
| Storage | Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive | $46.99 @ NCIX US |
| Video Card | Gigabyte GeForce GTX 970 4GB Video Card | $297.00 @ Newegg |
| Monitor | LG 22MP55HQ-P 60Hz 22.0" Monitor | $139.99 @ SuperBiiz |
| Prices include shipping, taxes, rebates, and discounts | ||
| Total | $838.60 | |
| Generated by PCPartPicker 2015-06-30 10:02 EDT-0400 |
Note I don't have much experience with screens so just picked one with high ratings, for gaming this rig will definitely be enough, for 3d CAD it might slow you down a bit.