Help with Multiple monitors to extend my desktop

Hello

I wish to use two monitors connected to one desktop PC to basically extend my desktop so that i  have more space on my desktop.

I have connected two monitors DELL 170FP and DELL D1028LR onto my DELL PC Dimension 3000 using monitor splitter cable plugged one end to VGA out on PC and other two ends to the two monitors.   The PC uses Intel(R) 82865G Graphics Controller but when i look into monitor properties i only  see one monitor, i.e. i do  not see the secondary monitor under Display->settings.

I can see the same display on both the monitors, however my objective was to be able to extend  the desktop by having one primary and other secondary monitor.

What could be the issue here and how can i make this work. Do i need to install additional VGA adapter, if so which one can i use?

Thanks
Paresh.