New RIG Plans, And +12v rail requirements

Could you please say how much money you able to spend?
Maybe we could put together a more interesting machine for you.
And about your +12v rail problem: I checked and your GT 440 need 90W peak to work (about 8A)
So it would be ok in one rail only, and the other one would power up the cpu.

Most of the smaller PSU's are not true multi-railed power supplies.
Single vs. multiple rails:
http://www.jonnyguru.com/forums/showthread.php?t=3990

Don't worry about it. Your Enermax 350 will power your system.

Vitornob is correct about your budget. You don't need 12GB RAM.
http://www.tomshardware.com/reviews/phenom-ii-overclock...
Look at that for some ideas.
You don't say if you are building new or cannibalizing an old rig.
You will likely need a new Win 7 OS as well. $100.

Be aware that you picked out a 3 dimm kit for a 4 dimm board. Get either 2 sticks of ram, or 4, do not run 3.
Corsair 16GB 4x4 kit $70 after rebate: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
or
Corsair 8GB 2x4 kit $40 (dont need heat sinks unless overclocking)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
other brands of ram are fine too, I just like corsair.

As for the power supply:
When a product does not have a review on newegg I tend to avoid the product even if I am not going to buy it from them. I would get a different power supply. As far as I can tell it should get the job done, but I would feel more comfortable with something other people have used and reviewed. I also would recommend a minimum PSU of 450W for home builds. They are not much more expensive, and it has a greater likely hood of not needing to be replaced the next time you upgrade your system, or if you want a better GPU, or more HDDs in the future.
That being said, you do not want to go overboard on the power supply, but you do not want to be so close to your minimum requirement that you have to wonder about it. And do not skimp on it. Everything relies on your power supply, not just for raw amperage, but for a consistent clean flow of power which will regulate and clean the power coming from the wall.

Thank you all for the feedback, I'm not considering any exact budget but around 400 dollars is probably it or let's say 300 Euros. Now regarding the RAM, I'm planning on doing some video editing and Overkill ram is needed for faster renderings. The OS I have ready a 64 bit one. And I still don't understand regarding the point of putting a 3 DIMM card on a 4 DIMM board is it a problem ?