I normally transmitted on FRS 8-14 which are hard set for low (.5 watts) and after I got my GMRS permission slip, I went to one of the other channels and set the HT to High power (a whopping 2 watts) I still couldn't see a difference.
I'll add that GMRS in New England is not popular because of the generally mountainous terrain, so calling out my call sign and asking if anyone hears me, was probably not going to work ever with 2 watts and a stubby fixed antenna.
Hopefully I'll be able to reach the repeater in the next town over.