Not familiar with this game, however, try from within the game to see if there is a settings tab - usually from the front screen.
In here you will likley find all kinds of settings such as sound, detail, physics and graphics.
In your case try with a resolution on 1024 x 768 which will reduce the strain on the GPU. Maybe turn the detail level down e.g. you may see less damage or the draw distance will reduce. This will reduce the strain on the CPU.
Further check what the settings for anti aliasing and anisotropic filtering are as these will slow your PC down if turned on high.