If all you want is a bright light, forget the 3-way and just put in a
150 or larger equivalent CFL. You CAN exceed the 100W max because CFLs use a much lower wattage and dont get very hot.The only thing is if you use a single bulb, you got to click the switch twice to turn it on /off. Not a big deal.
If you want an additional dim light, get another fixture or night light in same room.