Quality problem with video cd

hey guys i have an problem so thought that i should ask you indeed

I made an video file in wmv format with aspect ratio 4:1 and 640*480 pixels quality through windows media player
and when i converted into video cd through my nero make video cd option the quality deproved to a great extent.(320*240 pixels)

I am the person who rarely compromises with quality. so can you tell me an option to convert video files into video cd format without compromising with the quality.please