extending remote transmitter range

after opening up the driver's side knee panel, i noticed that the antenna rod for the extended range receiver on my concept 200 alarm was just under my gauges, and the 3 or 4 feet of wire was all coiled up.  i unraveled the wire, and fed the antenna up through the driver's side window pillar, and hid it in the roof about halfway across the driver's side visor.

i expected much better range with this change, but didn't notice much difference.  i think i was just barely passed 100 feet.  what's the normal range i can expect from a concept series alarm?  is there any other way i can modify this to boost the range?