I would reccommend a weather/texture add-on like Activesky 2012 which allows you to adjust ALL aspects of your scenery including runway lights. It will impact your system a bit though so you need to have a good CPU w/overclock and a decent video card.
Check out this thread for more info: http://forum.avsim.net/topic/286842-new-fsx-lights/
You might want to try that before buying anything to see if it works for you. Good luck!