Most Gauss speakers are big dollar replacements. Look up the model on-line and see what they are selling for. If the repair price is cheaper then an equivalent replacement then you decide.
The power amp is separate chassis located on the bottom of the cabinet. It usually is held in by 4 screws on the bottom of the amp. You will have to remove the speaker and the back panel to access it.
Most of these that I have seen that are blowing fuses are usually either shorted output transistors or a shorted bridge rectifier.