I think you need to go over the wiring and think about replacing the HIDs if they are at fault. However the high beams should still work even if the low don't.
check all light fuses and relays in the engine bay fuse box. also check fuse number 3 in the footwell (1st row third along).
I have my HIDs on a separate relay circuit direct from the battery (both the relay and HIDs are now cheap on ebay)