Quick questions on an ASUS motherboard

Hey I am getting a new graphics card for my PC, I have been getting heavily into Autodesk Maya and I currently have an asus cm6870 computer but the graphics is integrated and not dedicated.

I called asus they said I can get a dedicated nvidia graphics card without a problem with the motherboard or anything so I am pretty settled on a nvidia quadro 4000, I have been reading really good things for the cardfor what I need it for. My questions are:

-Would I need to install a new fan also?
-Will the card actually work with the motherboard without a problem?
-On a scale 1-10 of difficulty how hard would it be to do this myself? I don't know much about computer hardware specifically but always have been able to figure anything out at the end of the day