power source isolator needed?

As many of you know, I'm putting 62 leds in the headliner of my car.
I got to test it out yesterday, and I just discovered that if I use the car battery to power it, whenever I connect my audio source (1000W class D amp) to my circuit, the subs go nuts and start making all sorts of noise.
It's because my VU meter circuit (lm3915) shares the same power source as the amp.
I didnt come accross this problem before because I was using a 120VAC source with 5VDC output.
I'm not positive on the max. current draw. I'd say no more than 2 amps when the circuit is finally done. So is there a way to take care of this problem?

I was thinking that I could use another rechargable battery (I have a battery from my cordless drill in there now). I'd wire up a circuit so that the 2nd battery would only charge when I have the leds shut off. Then when I turn them on, it disconnects the 2nd battery from the regular car power and it works just fine.

Lemme know what you think.

I think, 2A additional load no problem for car battery. Maybe the cause of noise the GND-loop. Try driving the VU-meter input via 1:1 audio transformer. (canibalize it from old pocket-radio or cordless-phone base station)

:? bah I am such an idiot, last night I thought of using a 1:1 transformer, but I didnt even think of putting it on the audio source, I thought I would have to put it on the DC power input which would have involved switching to AC then back.
That should solve my problem.
Thanks a bunch,