You should just be able to either
a) Use the 1/8" cable that comes from your speakers to your TV's headphone jack. If you need an extention, just get an 1/8" extension cable.
b) if you wanna go through your audio outputs on your TV, get a 1/8" to Audio cable, and make sure that the 1/8" end is a female, otherwise you'll need a 1/8" coupler. You should just be able to plug the audio cables (red/white) into your audio outputs.