Please don't be rude, I'm not looking for making a living on bitcoin mining, I'm just experimenting with it a bit. At least I would like to, but I can not use properly the GUIMiner. I reckon that I should be getting a bit better rates, like twice as good as now.

I don't see any option to enable processing by the GPU, I can only see my CPU in the list. My hardware: Intel Dual-Core E5200, 2GB DRR2 RAM, Radeon HD7730 2GB VGA.

I've already installed the AMD developer tools/kit, it made no difference.

It really looks like to me, that it only uses my CPU.

Screenshot: