So through work I have saved around 300$ dedicated to my computer and I don’t no where to best put the money in to maximize the gaming potential. Here is my current rig:
Motherboard - Gigabyte ma785gt-ud3h
Graphics card - ATI radeon 4670 1 gig pci-e 16x
Ram - (2x) - 2 gigs of ddr3/1600 mhz memory for a total of 4 gigs of ram
Processor - amd athalon II X4 620
Power - 700 watts

Being the inexperienced computer person that I am, I thought I would turn to the experts, Thanks!

Get a better motherboard (specifically an ASUS Crosshair) and install a 64bit OS and you should be good to play the game on medium to high (if overclocked) at a stable 50 frames per second and higher depending on the maps.

Perhaps you could go for a new video card, possibly one with DX11 so you can enjoy crysis 2 with all it's stunning visuals and tessellation, if you're looking for an ATI card, you could go for a 5770 for $150 or a 6870 for $250, If you want an Nvidia card, you could get the gtx 450 for $125 or a gtx 470 for $250, any of this cards can Run Crysis 1 On max settings, so I assume they will be able to handle Crysis 2 on high settings.

wow horrible ideas from those guys
you have a bad cpu/gpu an ok mobo itll work
620 sell that mofo on cragilists for 50bux
buy a phenom 955 best price/performance cpu great for gaming
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103808
you can go nvidia or amd but since you got amd mobo and when u upgrade it prob be able to do crosfire only so
gota get a 6850
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125348
25bux over budget but its worth it when crossfired max crysis1 on 1080res

Horrible suggestions yet you want him to spend a large amount of money on 10-15% better cpu performance he doesn't need or will see due to gpu bottlenecks?

*sigh*

To the OP, i recommend getting a gtx460/70 or a hd6850/70, then spending the rest on perhepirals like maybe a better monitor/speaker setup ect. Or just save it!

is buying a gtx 570, safer to buy at bestbuy or online? anyone?

What do you mean safer? I think you could probably find a better deal online but if your concerned about safety, just make sure you buy it from one of the bigger sites like NewEgg, TigerDirect or Amazon, they are very trustworthy. I've had great customer experiences with all of these sites.

is buying a gtx 570, safer to buy at bestbuy or online? anyone?

I just purchased an overclocked GTX 570 a couple days ago from NewEgg, it arrived to me last night in tip top shape even through a blizzard.

The real question is whether or not you are willing to wait a couple of days for what may be a better deal online, and if you want to put that much money stressed on your credit card or not?

To the OP: I think you should start first with upgrading your graphics card since it is two generations behind and rather low-end for that generation. After that, you should focus on upgrading to the Phenom II series if your motherboard can support it. The Phenom II X4's have especially good price/performance to date, while the X6's are made with the future in mind.

The Radeon HD 6870 is what I have in mind as your top choice of video cards, or you could wait until a budget fancy GTX 560 is released.