156 aerial booster

is ther such a thing as an aerial signal booster for the 156, one that may be better than standard, or any other way to get better radio reception? since fitting new headunit, reception has been pants, and aerial etc plugged in fine. im sure i need the bit behind the c pillar trim as the rear screen demister interferes with the reception when on, but is there anything i can do at the same time to "boost" the signal?