Wii u hookup question

Got the wii u to replace my older wii. As of now my old wii is hooked up to my onkyo receiver via the component cables then out thru hdmi to TV. No this receiver only has to hdmi inputs. I would like to get the better video setup by using the hdmi port on the wii but then it won't run thru my stereo. Is there a splitter for hdmi that can be used. Will the picture look that miche better using hdmi vs component cables. I could hook directly to TV and then try to get sound thru stereo. Trying not to have to fully reprogram my harmony remote. Thanks.

I'm asking if I have no more hdmi inputs left on my receiver if there is an hdmi splitter I can use or will I get same picture quality using component hookup with wii u