connecting old tv with new dvd

Yes, you can get AV to RF adaptors. I suspect your best bet would be one with to AV's in, one RF out, with a switch to choose which AV signal you want to watch. Unfortunately you cant connect the DVD through the video because most DVD's have copy protection which will cause them to flicker when connected to a video.

Had another look at the video, and it has RCA connections for audio/video, mono sound. So the tv doesn't have any AV plugs at all, just the RF and the two RCA. The dvd is AV with a yellow plug, and red+white stereo audio plugs.
Have seen a switch called Audio Video Signal Converter Switch PS2 XBox. It has a set of AV yellow plug and the red+white audio for up to three different gadgets. Perhaps that with some adaptors. Or is it possible to get a switch with one AV in, one RCA in and one RF out?

I don't understand what you mean by RCA. RCA is the type of plug that Audio/video cables use. Which makes me think that the two RCA plugs you refer to on the TV are a video input and a monophonic audio input. Where you've got a stereo appliance such as the DVD you'd just use one of the audio channels (normally the left) and just not connect the right. But whatever the situation, these days you can get adaptors that will convert just about anything to anything else.

Yes you're right, that's what I meant about the RCA. I think I'm getting the picture. Thanks for your help.

So long as you get a picture, you're doing something right.

If you have got an AV input, you won't need a switch box. Connect the VCR to the RF and the DVD to the AV.