Power Supply suitable for Nvidia Zotac GTX 285 AMP!

Hello guys,  

My system is:

Motherboard: Asus P5QL
CPU: DualCore Intel Pentium E5200, 2533 MHz (12.5 x 203)
Video: Asus Ati HD 4850 512 MB, 256-bit
System Memory: 2 x 2 GB A-Data EXTREME DDR2 1066+ (DDR2-800 DDR2 SDRAM (5-5-5-18 @ 400 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz))
Sound: VIA VT1708S @ Intel 82801JB ICH10 - High Definition Audio Controller (integrated in the mainboard)
HDD: Seagate ST3500320AS (500 GB, 7200 RPM, SATA-II)
PSU: Black Diamond 500Watt (brand: Point of View)
Monitor: HP LP1965 [19" LCD] 1280x1024

Since I am going to do some upgrades on my system, starting with the video card, i ordered Zotac gtx 285 AMP! first, and till the end of the year I am going to replace CPU with Intel® Core™2 Duo Desktop Processor E8600 (best CPU supported on my Mainboard) and monitor (something 22" or 24") .

The Zotac card will arrive till the end of the week I hope, so i need to buy a new power supply.
I was offered http://www.pointofview-online.com/showroom.php?shop_mod...

Black Diamond 650Watt:
+3.3V 36A
+5V 30A
+12V1 18A
+12V2 18A
+12V3 18A
+12V4 18A
-12V 0.8A
5V VSB 3.0A

I know that gtx 285 series require at least 550W PSU and (Minimum recommended power supply with +12 Volt current rating of 40 Amps.)
I am NOT going to use SLI.

So my question is will this PSU Black Diamond 650Watt, with the above specification, be enough to handle the gtx 285 AMP! and Core2Duo E8600?
Also how is the +12 Volt current rating of 40 Amps being calculated in this case? Is it summary of 12v1(18A) + 12v2(18A) + 12v3(18A) +12v4(18A) = 72A total?

Thank you in advance!
Have a nice day all!