Hmmm. Assuming you are using TyCapture... in theory, with the TV Wonder selected, a Crossbar button should be available in AbelCam on the righthand side of the initial Cam Config screen (the screen where you set Framerate, Name, etc.). Crossbar button should take you to the Input Selector dialog of the ATI driver. But in practice, there isn't really a universal standard that all TV cards follow, so perhaps TyCapture doesn't realize your Wonder is a TV card.

If you decide to try the TV Wonder again some time, one possible work-around (if Crossbar button fails to appear in AbelCam) is to go ahead and start the card up in AbelCam with it set to its default input (Tuner, apparently) and then use a utility like AmCap to access the driver's Input Selector / Crossbar dialog to change the input selection. Not pretty but it works