new hookup

i just got service yesterday. i have the d-tv hddvr setup.  my question is? i have an older style projection panasonic hdtv. it has no hdmi hook up on back.  it does have the standard red, yellow, green rca hook ups and also a s-video plug setup and the green, blue, red hook ups.  which will give the best picture quality and sound?  the installer used a  r,w,y rca hookup? is this the best or should i hit radio shack and get a different wire hook up?  any help would be appreciated. thanks.