Its the same PC. 1 TB don't mean 1000 GB. Its always lower. For me, I have 2 TB and the actual space is 1862 GB
For the GPU, the 7870 is certainly above 200 dollars mate but slightly higher like 220 or something. So if your budget is 220, I guess you should better go with the GTX 660
It will preform amazingly. HOWEVER, your CPU is kind of weak, so I think it will limit the performance of your card.