Too late now, but I'm pretty sure it's within the pokerstars TOS to let someone else log into your account in this situation. I can't find the page now, but I remember them using a power outage as an example. So, if you know someone not affected by the outage who you can trust with your username/password, they can sit in for you until the power comes back on.
You might want to fire off an email to their support just to confirm this, in case it happens in the future. The obvious warnings about giving someone your password go without saying.