Hello and welcome to the forums.
Your setup is indeed quite old and it may not boost or help your performance with better graphics even if you install a proper gpu.
I googled that hd 4200 is integrated gpu and if you have free pci-e slot, you could install there proper gpu. Now the drivers is another thing then, as I used to have hd4870 and before hd4850 and gt 710, but there is no updates for those drivers anymore and neither for your gpu. I can tell you, gaming wasn't fun at all.
My advice is, get a new pc if you really want better graphics and overall better performance. That's what I did