I wouldn't put much stock in a stationary bike power readout. Your riding position probably isn't optimal either. As long as you get your heart rate up and work your legs hard you've accomplished something. I put my bike on either a magnetic or hydraulic resistance trainer I the winter, when it's too nasty to ride. The resistance feels like climbing all the time. I end up with a low cadence, high torque ride. I've got no power reading, so I go by heart rate.