ASRock Z77 Extreme4 Socket 1155 VGA DVI HDMI 7.1.....
Intel Core i5 3570K 3.4GHz Socket 1155 6MB Cache O...
Kingston 8GB 2400MHz DDR3 Non-ECC CL11 DIMM (Kit o...
You'll be needing new RAM too as your current stuff is too high voltage for the newer platform.
I'd keep your current GPU as nothing new makes sense as the price will be way too high... add another for SLI action later on.
You should also consider an SSD to help things load quicker and for a more pleasurable experience in Windoze.
Those things would be my pick for your budget. Get yourself a Corsair H80i with whats leftover and you're set to go.
You should also add where you're from so we get a better idea of the places to look.
Also, welcome to TPU!
Sell your FX3800 and pick up another 470 for no extra money. They are selling for a stupidly high price and you'd be able to score a used 470 for the same, if not less.