BakedGoods: Hey man,
Quite simply, the comp isn't up to snuff. This is a very demanding game that even the newest computers can't run perfectly. I'd suggest if you're seriously interested in playing this game to upgrade.
The key things here at the CPU and GPU. The E5200 may seem to be 'faster' than the min specs, but the architecture is much different. Put simply, the Intel Core 2 Duo is a beast. The GPU is the lower of the 9xxx series, and it's video memory is definitely not 2Gb. What that's referring to is your system mem + video mem. The important thing about the GPU is the second number. So while your card is a 'generation' ahead (9xxx > 8xxx), it's actually the lower tier (x2xx < x8xx) and more similar to say an Nvidia 8200.
E5200
is a Core 2 Duo. It's Wolfdale architecture, the successor to Conroe. It's above minimum requirements, if a little short on cache (2MB). It overclocks very well, but you're not going to get to overclock it or upgrade it on a Gateway proprietary motherboard.
The GPU, though, is a disaster for this game. The 9200 is a little 8-shader chip made for, at most, video playback. The 8800 GT 512 that's the stated minimum is a 112-shader beast. You have an open slot for a better graphics card, with plenty of clearance, and this is an easy upgrade.
The biggest problem with upgrading is that Gateway is notorious for skimping on power supplies. The pictures show a 300W FSP model that Gateway and everybody else used in low-end computers at that time; it has only 14A at +12V, which is just barely enough for a low-power graphics card. (At least it's not awful, like the 300W Bestec they used earlier.)
For that reason, I would either figure on replacing the power supply or limiting my upgrade to a graphics card of 75W TDP. There are a few decent ones that do not meet the minimum requirement but are known to play the game anyway. My favorite of these is the AMD/ATI 5670 (look for a version with 1GB DDR5).
Even if I did replace the power supply, I wouldn't go for an expensive top-of-the-line graphics card; your CPU won't be able to feed it fast enough and will become a bottleneck. Something like an AMD/ATI 5770 or nVidia GTS 450 is enough.