Your going to get too much glare if you take a picture directly of the lights cause the camera wants to adjust the exposure for the available light, so the resultant effect is the shadows will be too dark and not hold too much detail yet the lights will be correctly exposed. It also goes the other way. if you didn't have the headlights on and just took a picture of the car with the available street lighting, the camera will adjust exposure so the car will come out correctly exposed, but you need a tripod for this otherwise your images will be blurred.
The Shutter speed will be alot Slower and the Aperature will be pretty big f/5.6 or less f/2.8, f/1.8, f1.4 (Aperature at f/5.6 is where the cameras Iris is almost open all the way kind of like how your eyes adjust to the dark, your pupils will be big to let in more light and f/22 the iris is closed down a lot, like your eyes the pupils will be really small and you will probably be squinting to reduce the amount of light hitting your eyes on a really bright sunny day on the beach without sun glasses.
However if you can, set your camera for f/5.6 or less and then turn on the lights, your headlights are going to end up being very bright.
Basically you need to take a picture of your car in a parking lot with a lot of ambient lighting, Then you might be able to have your headlights on and get the effect you want, this will be the best thing for you.
Don't use Flash as this will wash out what you're trying to achieve.
I don't know too much about the Canon A520, are you able to take control of the Aperature and the shutter speed like you can with a DSLR, this is ultimately what you want to be able to do.
If you can control the shutter speed, you should have a marking showing TV
Control of the aperature will have a marking showing AV, and then there is Manual (M) where you control both of these.
Hopefully this will have helped you
