What is the amperage for a stock 2002 toyota echo alternator?

What is the amperage for a stock 2002 toyota echo alternator? I saw somewhere online that its only 70a, but for a 'newer' car i think thats way to small. And even if it really is 70a, do you think that's enough to run an audio system with an amp that puts out 300w RMS? I don't have power doors or windows. thanks!!!