...you'll need to buy a digital to analog adapter like I did. The one I bought 2 years ago cost around $60 if I remember. The selection is a lot greater nowadays; I see Amazon has some in the $20 range here:
http://www.amazon.com/s/ref=nb_sb_noss/183-1764368-5101009?url=search-alias%3Daps&field-keywords=digigal+to+analog+audio+ . I'm sure other places have them as well.
There is no rca type audio out on my new hdtv nor is there an hdmi in port on my old audio system. How can I hook up my tv audio to my old system as I did on my last tv which was a crt tv.