Save your weed money and when you have enough buy a stereo to play the audio.
Man you're really missing out on some great audio in this gens games, I couldn't handle only using my TV for the sound output.
To answer your question, RadioShack has a cheap Video Component Adapter *RF Modulator* which allows you to connect Ant-in. SVid-in, component-in, and dual channel audio in through it's box.
It's about $29.00 here in town, I'm not sure what the price difference would be where you live.
*Edit*
Of course the one I posted is for a cheapie, but there are options similar to this which allow you to connect most of your consoles to it, then it connects to your TV/radio which take care of the RF problem too.