I think you are confusing hardware with software drivers. Your GPU is an AMD HD 6250 which is actually integrated gpu on the cpu aka an APU. You only use drivers made for that gpu (so no nvidia drivers). You cannot upgrade it as it is soldered to the board (both gpu and cpu seeing as they are the same piece of silicon). You may be able to upgrade to new drivers at AMD's website. Drivers are software that allow windows (and other operating systems) to properly use computer hardware.