I saw the specs of the computer and seeing that you only have 2 cores, and since Minecraft is very CPU cores dependent, it is not suprising that you are running it at 30 FPS. I would not expect any more..
I would not recommened putting the max framerate at unlimited as it can put heavy stress on the computer to do better.. Putting the framrate at 50 - 60 FPS limited might help increase a tiny bit..