Hello,
Your motherboard (the large circuit board inside your computer) has a PCIe 1.1 x4 slot, which should allow you to install a graphics card. However, most graphics cards are installed in a faster x16 slot, so whichever one you install, it will be slightly reduced in its performance.
Another thing is that you would require more RAM in order to play The Sims 4 at higher settings, but unfortunately the older DDR2 RAM which is supported by your motherboard is very expensive. I do not think the upgrades would be worth the money. I would probably advise you to get a new computer if you wish to play The Sims 4.
I hope this helps and keep simming,
Cody