Do you mean dual core processor? That's a bit different than adding another processor.
There are motherboards that support dual, quad, and hexacore CPUs.
These are the minimum system requirements to play that game. * OS: Windows® Vista / XP / 7
* Processor:Intel® Core™2 Duo E6600 or AMD Phenom™ X3 8750 or better
* Memory: 2GB
* Video: Shader 3.0 or better 256MB NVIDIA® GeForce® 8600GT / ATI Radeon® X1950Pro or better
* Sound: DirectX 9.0c-compatible
* DirectX: 9.0c
Your current hardware won't support the game. You would need to change the motherboard and CPU, at minimum, to play that game.