A Maxtor hard drive, eh? You're pretty old school
8600 GT was actually released as a gaming graphics card. Neither of GT620 or GT730 were released as gaming graphics cards. However, GT730 is easily the faster one out of those:
http://gpuboss.com/gpus/GeForce-GT-730-vs-GeForce-GT-620. It's about 2-3 times the speed of the GT620. I'm not 100% sure on how a 8600GT compares to these, but I'm pretty sure the GT730 beats it pretty easily. It's a decent all-purpose graphics card that can play games on low image quality settings and resolutions.
Personally, I'd keep saving a bit more and buy something that pairs well with the FX-8350. You've got a great processor (not the best objectively, but really good compared to your other hardware), and it deserves a great graphics card to show its potential in games. I'd go for something like R7 260X, cheap but extremely fast compared to an entry level card like GT730.
It would also help to have some sort of price catalogue from your local store and have us look through what's on offer.
Also, can you find out what your power supply is?