Last hope is to try resetting the PMU and PRAM, but I doubt this will help. Internal connectors don't typically get "unplugged" from drops, so I seriously doubt it's something simple as that if the backlight worked fine before. Chances are there is something now wrong with the backlight inverter, fuses, or the bulbs in the panel itself. This repair is going to cost more than $150, pretty much no way around that.
Steve