broken headlight lens

recently i noticed that my one headlight beam was lower than the other. I went ahead and tried to adjust the lens witht that knob near the radiator, but when i did that i just slumped again, and i noticed that the beam was vibrating. I looked into the headlight and i saw that the lens inside the housing was just slumping. Does anyone know of a quick fix i could use to correct this or am i looking at the purchase of a new headlight? Any ideas are greatly appreciated. Thanks. :twisted: