Hi Tim,
As for your powersupply, I tend to stick with Corsair or Evga. Here is a link to a 5 way comparison of 5 that fall in a range for what you're running. I have added a couple 750w units, which under normal circumstances would be glorious overkill but I am just going to call it room for expansion
.
http://www.newegg.com/Product/Productcompare.aspx?Submit=ENE&N=100007657%2050001459%2050001402&IsNodeId=1&bop=And&CompareItemList=58%7C17-438-014%5E17-438-014-TS%2C17-139-028%5E17-139-028-TS%2C17-438-025%5E17-438-025-TS%2C17-438-026%5E17-438-026-TS%2C17-139-051%5E17-139-051-TS&percm=17-438-014%3A%24%24%24%24%24%24%24%3B17-139-028%3A%24%24%24%24%24%24%24%3B17-438-025%3A%24%24%24%24%24%24%24%3B17-438-026%3A%24%24%24%24%24%24%24%3B17-139-051%3A%24%24%24%24%24%24%24
The EVGA 600w is the least expensive and would server your immediate needs well.
The Corsair 600w is also inexpensive and would do the same job.
The EVGA 750w is really inexpensive, boasts a great warranty, and offers a lot of power for little cash. Lots of room to upgrade. I do not like the 4 +12v rails but that is preference really.
The Corsair 750w is the most expensive on the list and for good reason. It has a great warranty, modular cables, single high amp +12v rail, and unbeatable build quality. Modular is a great feature and once you use it once you'll never want anything else. But it is entirely unnecessary.
The EVGA 650w is the 2nd most expensive on the list and has a ridiculous 10 year warranty and is also modular. Again EVGA has chosen a 4 +12v rail assembly which doesn't mean anything bad but is personal preference.
TL;DR
I would go with the Corsair 750w if it was my build.
Now about upgrading your rig for better performance at a 100$ price point.
I would suggest (especially if you go with a 750w psu) to try your hand at overclocking. In that case, I'd suggest getting
http://www.newegg.com/Product/Product.aspx?Item=N82E16819116899 instead of your 4570 currently and then spending another 50$ - 60$ on
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181030 . You didn't mention what case you'd be using but a single 120mm shouldn't be a problem