Where are you located? It is best to look up local prices.
While not perfect, FX-6300 should be ok to game on lower resolutions. Personally, i'd spend more money on GPU than anything for best return on investment. CPU will help, but it is not much help, if GPU is a slouch.
You have not mentioned if you want a new monitor or whether the existing one will suffice.
Anyhoo, if i were you, i'd try to upgrade the PSU to 700-800W minimum, as then it will be a one time expense and will help cut down on repeat purchases with future upgrades.
Something like this:
http://www.newegg.com/Product/Produc...82E16817153198
$90 - $10 instant rebate - $20 mail in rebate card
However, there are fully modular PSU's that go for sale on Newegg. I'll sign up with them for promotional mails, to take benefit of such promotions.
Get a decent GPU which will hold you for a couple of change of seasons. Say a 290 or 290x?
http://www.newegg.com/Product/Produc...09%20600473871
310-$20 gift card - $30 mil in rebate. $260 which the lowest 290x has been reported at iirc.
Good 290s were much cheaper last week, may be demand saw the price go up. So right now 290x is a better buy for your money. If you don't mind used, you could look up something used on ebay.
With the rest of the money, i'd just add more to buy a good SSD with nice read and decent write speeds.
disclaimer: some buy from Amazon for better return terms, but the things are a wee bit costlier on amazon. You could also check BHphotovideo and their prices for something you may be interested in.