|That card only draws 20W, which is less than 2A@12V. Depending on your 12V amp rating and the other hardware in your system you may be able to get by.|
What games are you looking to play? That would determine what you need.
The Dell link below has some specs on that unit but it doesn't give the power supply specs or the processor type so I can't calculate the load or available amps on the 12V rail.
If you go to the Dell site and enter the service tag number from the rear of the case you should be able to get the exact specs.
As far as a graphics card goes, you need a low profile card. The card you listed has a low profile bracket included. If you get anything that would be considered med to high end, you will need to change the power supply.