using Samsung LE32R88BDX as a monitor,

I recently bought a Samsung LE32R88BDX TV and I was going to use it as a secondary display on my PC, after connecting my pc (geforce 8 8880 GTX) to it via the TV's VGA input, and seeing how sharp it was, I considered using it as a monitor.

Heres where it gets complicated, When connected with the VGA the picture looks as good as a monitor, but the maximum resolution it will take is 1366x768 (the native res), this fine for the desktop, but not sufficient for games.
When I connect from the graphics card s-video to the tvs component input the resolution can be put much higher, but the quality on the desktop is fuzzy and poor and text is hard to read.
Somebody said VGA has a limited maximum resolution and suggested a DVI to HDMI cable, I tried this and the native resoloution of this is 1280x720??? (why is this different to the VGA?) The res for gaming is ok and the desktop quality is acceptable but not as good as the VGA cable, this is what is stopping me from using the TV as a Monitor, I have played around with the nvidia settings, like the custom resoloutions, but im not really sure what im doing with the advanced timings, but I think its the cable limitations rather than settings thats causing the lesser quality.
So basically I just want to know if I am doing anything wrong or if there is some way of achieving a crisp image like with the VGA input and still be able to play games at high resolutions, either a setting or some sort of cable config.
Can the VGA input have some sort of DVI adapter plugged into it? or would it still be limited to 1366x768?

Thanks