1. Open ASUS Driver Download page:
http://support.asus.com/download/download.aspx?SLanguage=en-us
2. Fill in/select model in the box like the pictures below and click search:
3. The a pop up windows Will open and select Windows 7:
4. After that scroll untill you find the VGA and click on the [+] to expand the graphic driver list, and select the last One, Download and install:
Note that the Driver details should be:
ATI Mobility Radeon HD 5470
8.680.0.0000