I'd like to extend the display of my ASUS N53SV-SZ038V to two external monitors.
The laptop has one HDMI output and one VGA output. I have each connected to an external monitor. The problem is that it only allows two displays to show at a time (either laptop display + 1 monitor or 2 monitors). This is highlighted below:

The laptop has integrated Intel HD Graphics 3000 on the i7-2630QM as well as an NVIDIA GT540M. Whilst I don't think that either can support 3 displays directly, I was hoping that I might be able to offload one of the displays (or more) onto the graphics card.
After going into the NVIDIA control panel, I saw the below and thought there might be a way to rearrange it, but it appears not:

It would be much appreciated if someone could provide some guidance on whether or not this can be achieved, or indeed any other suggestions.