as dave says, you will need an audio cable as well which ever method you choose (either VGA or HDMI) no audio is sent down those cables. If you have an AV Receiver, connect the audio out from your MacBook to your AV receiver with a TOSLINK cable.
If you haven't, then depending on the route you go down video wise, you will need to connect the MacBook to the TV with a 3.5mm to 3.5mm cable if you are using VGA, or a 3.5mm to RCA cable for HDMI - one of the HDMI's will have this as an alternate audio input. I have a Bravia myself and thats what my inputs are like, yours may be slightly different so double check them
