Go onto support website for Toshiba and locate your Laptop and select your drivers. But my guess is that Toshiba won't support your laptop with updates for Windows 8. Also, Google this question and their may be others who have done exactly as you have.
Hope this helps.
answered Jan 06 '13 at 20:02
If you are using the mobile Xpress Chipset 1250 by AMD, the closest driver you are going to get is the Vista version here assuming you are using 32bit OS:
answered Jan 07 '13 at 19:06
yep your system is no longer supported and other than generics with almost n hardware acceleration that windows comes with, there is nothing you can do. (if you want you can try the amd driver updater whch will scan for any AMD GPU and update it to the latest compatible driver but I don't think it will find anything for your system )
As a last ditch effort, you can edit the driver inf's to support your card and just do trial and error installations but there is a good chance that you will render windows 8 unbootable as compared to windows XP, windows vista, 7, and 8 are less able to handle forced bad driver installs
answered Jan 07 '13 at 21:51