I have a Dell Inspiron 518. I dont believe any parts on it were custom, my parents bought it almost 2 years ago for me. Ya i was curious about the card that the guy above mentioned, it was a bit more reasonable, would the 9800 GT be decent to play the game? Also, what do you mean they cost additional power? Anyways i really appreciate your help:D you've helped me a ton.
I was afraid of that. Here's your computer inside the case. You have sufficient room to run a decent sized video card, but your power supply doesn't have any additional power cables for running a higher end video card. Period. Not even any you could adapt over. http://reviews.cnet.com/2300-19017_7-78-4.html?s=1&o=80
So basically you could make it work if you swapped out the power supply AND the video card, but at that point you would also want to upgrade the case anyways to get better cooling for the video card since the fans in that case are pretty underwhelming.
Your only real option is going to be a video card that doesn't require additional power, such as this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121353
That isn't going to play the game well, but it will play the game. If I were you, rather than go that route though I'd consider a more substantial upgrade.