On low beams and in your standard lights that are not meant for HIDs, what you are getting is what it can offer. The range will definitely reduce and if you try to adjust the low beam of your car, the high would be moved upwards accordingly.
I would recommend you to put HIDs in high beam as low beam is what we require mostly and we should have enough visibility on the road.
p.s. take your car to any electrician at night and he'll do it for you. It's not a big thing.