If you the circuit diagram of stabilizer then create a step down stabilizer it convert 12 v to 6v or whatever you want.It really very easy go to the electronics 4 you magazine ,there you will get the circuit diagram for converting 12v to 6v device.
Bur amd processor with 1GB ram.80GB hard disk is enough for you for storing new game etc. Actually amd processor is good for playing game.Put a good graphic card.This configuration is enough to play games.
If you want go for desktop,then your configuration will be like this: 2GB ram,intel 2 dual core processor,250/350 GB hard disk.If you want to take lcd then go for accr.It will comes around Rs 15000.If you want to go for laptop then hp is good.