Please help :(

I've got a 32" toshiba hdtv (hl86) and a 7800 gt video card.

I've connected my computer(windows vista) to my tv via the vga cable, the problem is that I can't get the tv to show 1360x768 properly. It overextends the desktop way too much in all directions. I tried to decrease the horizontal and vertical views but it has that feature grayed out. I can do 1280x1024 but its a 4:3 ratio that leaves the sides unused. I also tried to connect via the svideo cable but it will only go to 1024x768. I've got the latest drivers for my video card installed and I've tried to look for anything in the nvidia control panel to fix this but no luck.

If anyone could help me I'd be very greatful!