Hi there, Sorry I didn't see your question! The VGA box needs to go through your PC. So the connections would go something like this:
PS3 >> VGA BOX >> PC (which has the right spec plus nVidia Geforce installed) >> TV
I will create a diagram and put it on this hub: http://hubpages.com/games-hobbies/nvidia-gaming-in
If possible can you leave a comment there if you need anymore help, as I often miss the questions?