To increase the basking spot temp
1. get rid of bedding, go to paper towels or at least decrease the depth of the bedding
2. be sure to use a thermostat. Get an infrared thermometer. You can get one for like 18 bucks from reptile basics I think. They work great to see just what you temp is at a spot in the tank.
3. consider a bigger under tank heater.

To increase ambient temps
1. if you have an aquarium, cover 2/3rds to 3/4 of the top with foil covered cardboard. (this will also help with humidity)
2. make sure your aquarium is on an inside wall in the home, not near a window or on a colder outside wall.
3. Consider insulating 3 of the 4 walls of your aquarium on the outside with the cardboard. (Aquariums don't hold ambient temps well at all)