You will not be happy with anything you can find that will put a computer screen onto a TV.
My TV with S-video can almost reproduce a usable picture from my laptop, whcih has an S-vieo out port, with the laptop set for 1024x768. The picture on the TV is the same shape, and the icons are recognizably the same icons. None of the text is legible, though.
Dropping to 800x600 is better, but still rough.
If you don't even have S-video, then you're S.O.L. for getting PC picture onto a TV. Standard-def TV just doesn't have the resolution for it. As pointed out above, 480 lines vertically, although it's 480i, not p.