the GPU upgrade will be pointless on a stock FX 6300. Get it to 4.5 Ghz or get an FX 8320/8350 when you can, and then by that point the PSU will be on the weaker side to handle a real GPU.
OC the FX 6300, get 2 x 4GB 1600 mhz, and you will be pleasantly surprised. the FX 6300 really needs to be OC'd to be taken seriously, ive seen considerable gains personally from a bump up to 4.4 Ghz on a 6300, granted i was testing on older games (bio shock inf, metro 2033) as it was a while back. I cant imagine much has changed, with games increasingly becoming more demanding.