Looking to upgrade my system

[TheRooster]

Hello,i'm looking to upgrade my current PC,the specs as of this post:

Athlon II X2 250 3.0GHz
Sapphire HD 4670
1x 2GB Stick of DDR3 1333 RAM
Corsair CX400 PSU
640GB Hard Drive

And i'm still stuck in the Dark Ages with Windows XP Service Pack 3

I'm currently looking to get a stronger CPU,a healthier Video Card (The HD 4670 is on life support) another Stick of RAM and Windows 7 64-bit,here's what i've been looking at for said upgrades:

XFX HD 5670: http://www.newegg.com/Product/Product.aspx?Item=N82E16814150535

Athlon X3 445: http://www.newegg.com/Product/Product.aspx?Item=N82E16819103872

G.SKILL Value Series 4GB DDR3 1333 1 Stick RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231423

Windows 7 64-bit: http://www.newegg.com/Product/Product.aspx?Item=N82E16832116986

The most Demanding Games i would be playing are Shogun 2: Total War and Civilization V,though i usually play much less demanding games,i could also use a better CPU Cooler.

And if it matters much,i'm planning on buying this in August when i save up enough money.

 

[etk]

I'd hold onto your CPU for a while longer, or just up and get a phenom x 4 BE, prob a 955. This will only be marginally more expensive @$110 and better performance. Plus this would put you at the end of your am3 upgrade path.

I'd get another 2gb (not 4GB) 1333 stick of RAM to run in dual channel

I'd spend the difference on a 5770 instead of that 5670.

What are your CPU temps at now? You might consider a mild overclock even if on stock fan.

 

[TheRooster]

I could wait for the CPU Upgrade,is there any software that can test CPU Temps though? Reason i ask for a cooler is because my computer froze up then shut down when i was playing a game,when i restarted the system,the CPU Temp Rating (Via Biostar BIOS) was at 75 C.

Does Dual Channel 4GB perform that much better than non-dual Channel 6GB?

Bit paranoid about heat,considering my house doesn't have Central Air...

 

[etk]

No software is going to be better than your BIOS for reliability, just enable cool n quiet and let it do its thing.

For most people, 6GB SC would be faster in win 7 while 4GB dual channel would be faster in XP, but I think $20 could be better spent in your build than on extra RAM.

75 is really hot for stock clocks. Get some thermal Paste and remount your HSF.