By the way is it hard to dev this game?. And also if the server is already running in a PC with a spec of Dual Core + 2gb how many percentage should be my CPU Usage?
I don't have a dual core, but it works with Phenom II x3 740 and single-core Intel P4 so I think you should be okay just to test things out. I'm not sure if I can say the same if you plan to use that for a public server though.