Nvidia GT 640 to work on my 300W PSU?

I am planning to upgrade from my terrible intel hd graphics card to the GT 640. Now on the manufacturers website it says it requires 350W but I only have 300W? I have been told by some it would work, and by some that it would not work. So I need some clarification. Will this GPU work on my computer?

This is the GPU that I want: http://www.newegg.com/Product/Product.aspx?Item=N82E16814130795

I have a dell inspiron 660.(Desktop sized, not slim one)

CPU:

Intel Core i3 2120 @ 3.30GHz 
Sandy Bridge 32nm Technology

Motherboard:

Dell Inc. 0XR1GT (CPU 1)

Hard drives:

932GB Seagate ST31000524AS (SATA)

Optical Drives:

PLDS DVD+-RW DH-16ACS

 

(just in case any is needed)

Yeah.

I can use the card?

Definitely.