I own the above mentioned laptop. I was running Win 8.1 x64 OEM on it up until recently when I decided to go back to Ubuntu.
The problem is on Windows with latest drivers it nicely detected, that I have both an AMD R4 w/ 1 GB VRAM and an AMD R5 w/ 2 GB VRAM installed.
On Ubuntu with latest Catalyst installed from AMD's website it shows only AMD R4. inxi -F gave the following output:
Advanced Micro Devices [AMD/ATI] Mullins [Radeon APU A4-6000 with R2 Graphics] X.Org: 1.16.0 driver: fglrx Resolution: email@example.com GLX Renderer: AMD Radeon R4 Graphics GLX Version: 4.4.13283 - CPC 14.501.1003
Is there a way to get most of my system again?