Aspect ratio, size conversion problem, 4:3 to 16:9

Hi there,
I have been trying with different tools and settings to convert a video file to eventually burn to a NTSC DVD together with another video file.

The file is 480 x 360, ratio 4:3, 29 fps

The other video file has ratio 16:9 already and 29 fps.

I have tried with VirtualDub using different filters for resizing.

I also tried a tool called Video to Video which have worked without problems before until this video file started to bug me.

Whenever I convert it, it only ends in the video image getting black bars on the side, not in the bottom as expected.

Maybe I am using the wrong filters or settings. I am not sure.

Is there any specific settings that need to be set in VirtualDub filters for instance to get a better sized image? I want it to be like widescreen, not like a square image in a black box, if you understand what I mean....

Thank you in advance!