A graphics card is a piece of hardware already inside your computer which handles the display, and the grahics card drivers are the software programs that it runs when doing this.
Most problems viewing 3D graphics, including performance issues, are caused by having old graphics card drivers installed for your computer's graphics card. You can't get OpenGL drivers separately, it has to be supported by your graphics card drivers. Many manufacturers let you download the latest graphics card driver software free of charge from their websites, and this should include OpenGL drivers. When updating your graphics card drivers, it is important that you use the software that is specifically designed for your graphics card.
