The new drivers most likely came as a self extracting zip file.
Double click on the file on your desk top, and i hope it will give you the option to extract the drivers. Pick a place to put them. I personally would create a new folder on the c drive called 'graphics card driver' and put them in there, but the choice is entirely yours.
Once the files have extracted, i would go to the card in device manager, double click on it to open its properties, select the drivers tab, and hopefully there will be an update drivers button. click on it, and let things run their course.
Unless anyone else has a better idea.