My Windows 7 detects only my internal display adapter and wont show my external,

Hello,
Few days ago after seeing my index performance and clicking ''View and print detailed performance and system information'' I saw that windows is showing only my internal graphics card which is intel HD 4000.However besides the internal my Laptop has an AMD Radeon HD 7730M so I was wondering if the windows does not show this display adapter does it mean that my laptop runs only by the intel hd 4000?I tried checking it through ''Run''-''dxdiag''-''display'' and again the only display adapter i could see there is the Intel HD 4000.I tried testing it by playing World of Warcraft on ultra and i could get max of 30 fps.Then i thought that the video driver which was downloaded from the AMD site instead of Dell Support  could be causing the trouble but changing the driver didn't help.In addition I am using Dell Inspiron 7520 SE.

Cheers