Canon EOS 350D (Rebel Xt). My camera always reads 30 Sec shutter speed. Please help!?

My Eos 350D, does not respond to light sensitivity. Always settles down to 30 Sec shutter speed in Av, P modes. In T mode. due to shutter speed, the image is over exposed. Canon asks 220$ to fix. Firmware update will fix this? Is there an easier way to fix the problem?