Don't feel too bad, I've bricked microcontrollers too when I was new to them. Break this up into steps.
First, unsolder the components. The crystal is that rectangular silver thing under the big black ATmega chip. And under that you'll see you tiny little chips that look the same, those are the capacitors.
Then you'll need something that generates a PWM signal, like another microcontroller, or a function generator. Have either?
When I bricked my stuff, I just bought a new microcontroller. You can always use the new one to unbrick the old one.