Counter Stirke Source uses the Source engine
Unreal uses the Unreal Engine
Both require different hardware settings and if the developer who purchased the engine tweaks it then you'll have to look at those game settings.
Here are the specs required for the Unreal 3 engine:
Graphics: Geforce 6 series
Graphics: NVIDIA 6800GT/Ultra or 7800GT/GTX SLI
You're video card is not mentioned.
his video card is mentioned its a ati hd4200 igp