Hey there,
If it is laptop you are trying to upgrade then forget it. Laptops cannot be upgraded much. You can upgrade RAM but not the processor and GPU.
Upgrading the processor is more like changing the laptop from inside. It is recommended to buy a new laptop if u want a CPU upgrade.
Upgrading RAM is possible in your laptop up to 4GB (according what I know).
If your laptop have a free mini or micro expansion slot then the GPU can also be upgraded..
This might give you some idea about GPU upgrade:
http://www.pcworld.com/article/148909/maxlap.html
This might give you some idea about RAM upgrade:
http://www.wikihow.com/Upgrade-Your-Laptop's-RAM-Memory
If u have a high budget for this update you are looking forward to do, then I recommend you to buy a desktop with it.
You can play games in high performance in it too....