mbp airport turning off and have to reboot to get it back on

I've had my mbp for about 2 years and never any problems with using wireless.

This problem started happening about a week ago: it usually happens towards the end of the day, regardless of how much I've been using the laptop throughout the day.

The airport will turn itself off and it won't let me turn it back on. In order for me to get the wireless working again, I have to restart my computer.

It happens both at home and work with different wireless routers/connections.

After I reboot, sometimes it will continue working for 30 mins or so, sometimes it will only work for a few minutes.

Any ideas of why this is happening or if there's a way I can fix this myself?

It's still covered under applecare, so I can bring it to a store if need be.

thanks.