To put it bluntly: your rig is inadequate for gaming.
You have an integrated video card. These are not made for gaming, especially at a resolution like yours.
Your processor was a mid-range CPU that's now outdated by a long shot.
There's nothing you can do software-wise that will help you gain more FPS.
The only thing you can do is buying a new computer all together. Your CPU is too weak to handle new video cards thus you need to upgrade those two, which in turn basically means you need to get a new computer.
