Sorry to hear about your problem. I have a few solutions for you.
But, Before you attempt any of these, you may want to uninstall your current driver. It should ask you if you want to uninstall during the setup wizard on the driver download from the AMD website.
1. Have you tried going to the AMD catalyst driver site? I figure you already have, but just in case,
http/sites.amd.com/us/game/downloads/Pages/downloads.aspx
On this page you are gonna want to click the "download now" link underneath "automatically detect and install"
But, because you know what your GPU is you can always just click on the download link of the corresponding GPU.
Run the download and you will be guided through a setup wizard.
PLEASE NOTE: Your screen may go blank, black, or turn off during the installation. This is completely normal, so dont freak out if this happens.
2. You can go to the dell website to get drivers and updates, HOWEVER this will only work for windows 8. You are gonna want to go to this link:
http/www.dell.com/support/drivers/us/en/19/Product/inspiron-15r-se-7520
Under the "video" tab you will be able to download the appropriate driver. I would recommend downloading the AMD and Intel drivers, just to keep your laptop up to date. PLEASE NOTE: After any new installation, it is a good idea to restart your PC. I would recommend doing so after the installation is completed.
Unfortunately, if these 2 methods do not work, the only option left is to use a modded driver. The current catalyst updates are supposed to be released through the manufacturer's website. Many windows 8 laptops from a variety of different brands have been having the very same problem you are having. Until dell releases a driver specific to your model, or AMD is able to patch whatever the current problem is, you are going to have to use a modded driver.
This is a dell support page on using a modded driver, I think you may find it useful:
http/en.community.dell.com/support-forums/laptop/w/laptop/updating-your-ati-video-card-drivers-to-the-latest-catalyst-version.aspx
Hope this helps. If not, post what your error messages are, I could offer you more help that way.