2002 BMW 325 Headlight Problems

My car is a 2002 BMW 325CIC converible. The car has 150K miles and it is a great car. I have bi-Xenon head-lamps. My problem is: The headlights in the car work (i.e, they turn on) but they do not illuminate at all. At night, I can NOT see anything as the lights are barely on. When I turn the light level to the front for HIGH beams, ALL the headlights go off. Now, if I push the level to the back, they turn on BUT I must keep the level pushed back to get the high beams to work. That is, I have to drive with one hand on the wheel and the other pushing back the high beam level to get lights to see the road.

Any idea what the problem could be? Please advise. I appreciate your help.

I can be reached at [email protected]. Thanks.