ati - Steam not detecting the right AMD Radeon drivers on Wine

I have recently installed ubuntu on my system, which has a Amd radeon hd 7850.
The fglrx drivers installed just fine, and the system detects the right card (Pitcairn 7850)
after playing with amnesia on native steam without encountering any problems, I've decided to install windows steam using playonlinux. I've installed the game Counter Strike Global Offensive, but when it boots it detects a ati radeon hd 3200 series and says that it doesn't support the game, and then it crashes.
Here are the System Info on Steam:
Scheda video:
Driver non rilevato

Nome driver DirectX: ati2dvag.dll
Versione del driver non rilevata
Versione driver DirectX: 6.14.10.8681
Data del driver non rilevata
Intensità colore desktop: 32 bit per pixel
Scheda DirectX: ATI Radeon HD 3200 Graphics
VendorID: 0x1002
DeviceID: 0x9620
Numero di monitor: 1
Numero di schede video logiche: 1
Nessuno SLI o crossfire rilevato
Risoluzione visualizzazione primaria: 1920 x 1080
Risoluzione desktop: 1920 x 1080
Dimensioni visualizzazione primaria: 20.00" x 11.26"  (22.91" diag)
                                        50.8cm x 28.6cm  (58.2cm diag)
Tipo bus primario non rilevato
VRAM primaria: -2048 MB
Modalità MSAA supportate: 2x 3x 4x 5x 6x 7x 8x
I should also add that after it crashes the screen kind of "shrinks in size": the desktop only fills part of the screen and i have to restart unity through the console.