Here's a 3 watt booster for Nokia cell phones.

http://pluscellular.com/nokia2.htm

ExPro 505DB Full Duplex 3 Watt Booster Kit

The ExPro 505DB Full Duplex Antenna Booster solves major problems
encountered by cellular phones used while driving, such as, unstable
reception, unclear vocal quality, difficulty accessing calls or calling
out, and even calls being disconnected. The ExPro 505DB will boost
your handheld cell phone to a full 3 watts.