It will most likely physically fit in your case, but work correctly? I Doubt it.
You will have to use adapters, as your PSU won't have the correct plugins.
Beyond that your current PSU is not rated with enough power for that card.
Dell PSU's are rated strong amp-wise on the 12 volt rails, even though the overall wattage is not so high. If you have minimal hardware, like a single harddrive, single optical, no other add in cards etc, it MIGHT work, but there would be no guarentees.
I would advise against buying the card, unless you are willing to spring for a new PSU as well.