Is there a way to get HD audio for Turtle Beach headphones on a TV that has no HDMI input?

I just bought myself a pair of Turtle Beach headphones yesterday and I'm having a bit of a problem. I've got the audio converter that you plug the fiber optic cable into, but, of course, this uses up the port on the Xbox for analog A/V. Now, my TV isn't HDMI-compatible. It only has the yellow/red/white RCA input on the back of it. Is there any way to get the audio/video, or atleast the video, to the TV? As in, is there any sort of converter that plugs straight from the HDMI port on the 360 into the RCA plugs on the TV? For reference, I have an older Xbox 360 Arcade so it doesn't have the fiber optic connection in the back