If your TV doesn't have a VGA input, then yes, and you will need a 3.5mm RCA to composite audio adapter and then a 30ft composite audio cable. Which probably won't work, unless your TV has some means of letting you select an audio input to go with the PC/VGA input. If you have a surround receiver, that could do it. And a mini-DisplayPort to HDMI adapter won't work either, because it wasn't until the 2010 models that Apple included support for audio. Otherwise you have to rely on dodgy firmware hacks which could very easily break your computer.
The simplest solution is to get some kind of stereo or surround receiver to stick between your laptop and TV connection wise. Another option would be to get a set of external speakers for your laptop, and then a 30ft extension cable for them, set them near the TV, while plugged into your laptop's headphone jack.
This whole process is a lot more involved than a lot of people think, and at this point I'd advise you just cut your losses and run while you're only out $40 or so for the adapter. You can probably find a use for that at some later point anyway. This particular rabbit hole goes quite a bit deeper, so might be best to turn back while you can still see daylight.