You can boost the signal all you want, which in some cases may help. But in order to increase your range, you need a better antenna/receiver combo.
I can't believe nobody seems to make a high gain FM radio antenna! I've googled to no avail. The Laird unit is the best I've found so far.
If anyone else wants to try, look for a 1/4 wave 3 meter VHF no ground plane whip antenna.