Need upgrade advise

I haven't keeping up PC's news for the past 2 years. I would like your help. I want to upgrade my PC to play Just Cause 2. Since this game doesn't support Windows XP, I want to install Windows 7 and other hardwares if needed at the same time.

I want to play game at resolution 1650 x 1050 with mostly high-detail settings (some medium-detail settings are fine too), 2xAA, and 4x anisotropic filtering in decent frame rate (30fps or 60 fps depending on games).

My current PC:

Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor BX80570E8400
GIGABYTE GA-EP35-DS3L LGA 775 Intel P35 ATX Intel Motherboard
CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X2048-6400
SAPPHIRE 100245HDMI Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card
RAIDMAX SMILODON ATX-612WBP Black 1.0mm SECC Steel ATX Mid Tower Foldout MB Computer Case With 500W Power Supply
Samsung 2232GW 22" Widescreen Monitor

I also want to keep the cost down too.

I am thinking about adding 2 more GB of DDR2 800 ram and get MSI N460GTX CYCLONE 1GD5/OC GeForce GTX 460 (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card.

What do you think?

Thanks!

I think you are on the right track. To save some coin, dont get an OC version of a GPU when you can do it yourself for free.

As far as your ram, make sure its the same stuff or at least the speed, timings, and voltage.

I would also consider getting a better quality PSU as soon as you can. Most Raidmax are pieces of junk.

Looks like your sig is out of date...

For the memory, I have 2 options.

1) Get one more set of CORSAIR XMS2 2GB (2 x 1GB) DDR2 800.
http://www.newegg.com/Product/Produ...40-Pin_DDR2_SDRAM_DDR2-_-20-145-590-_-Product

or

2) Get a set of Kingston HyperX 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 Desktop Memory Model KHX8500D2K2/4G
http://www.newegg.com/Product/Product.aspx?Item=N82E16820104073&cm_re=ddr2-_-20-104-073-_-Product

The price is $52.99 vs $89.99.

If I go with option 1, I can use my current CORSAIR RAM with new set of CORSAIR RAM and save some money.
If I go with option 2, my PC will be slightly faster, and I will have 2 extra sticks of RAM.

What would you do?