First off, what is your budget? 2nd, why would you add a vid card from DELL?? Configure the Dell with the most basic options. Then anything thereafter, add it yourself. If you can fix cars, you can upgrade a computer. Especially with a vid card. Pop open the dell, put in a new vid card, you're done.
And both vid cards you listed are complete pieces of shit. I bought an 8800GS off a beyonder for $60 that leave them in the dust.
You have a couple of photos that are great... you must be very good at photoshop!