I'm assuming you nabbed a generic picture and there is actually something occupying the top blank slot (where the circled "3" is) on your computer. Is that right?
Dell's website isn't much help, but they do list a VGA connector (the circled "2") as being standard. Whether they mean on a separate card or onboard is not clear. I'd venture a guess that it comes with onboard video which you may not be using. If so, you can (possibly) disable the onboard video in the BIOS and get what looks to be about 256MB of RAM freed up. (4.00GB actually equals 4096 MB, subtract the 3.87 Windows is showing, account for a rounding error, and you're at 256MB.)
If you are not comfortable dealing with the BIOS it is better to ask questions before doing anything
. Dell doesn't usually give you much to change around to begin with, but if you disable your onboard video and don't have a separate card you will be facing an even more complicated job - and possibly temporarily be without any video at all until you fix it.
I'm definitely not trying to scare you into paying Dell's $100 "protection money" extortion, just advising you to ask questions about anything you are not 100% sure of.