cable to connect iMac 7 to HDMI LCD TV

I've got an iMac 7,1 running OS X 5.8. We just purchased a Sony LCD TV w/ HDMI input capability. What would I need to purchase to run my Mac thru my TV? All that the TV manual says is the PC cable needs to have a ferrite core. In other discussions it looks like you also need to have an audio cable running from the computer to the TV b/c the computer doesn't support audio thru the output (computer purchased about two years ago). Am a complete tech geek unless things are spelled out for me! Any help will be greatly appreciated though!

Thanks 🙂