Your best bet in this case unfortunately is what you are already aware of..

Which goes something like this:

1. Obvious police report to local authorities (check)
2. File a small claims (based in your country varies) - here in the US its anything $1,000 or less (based on state)
3. During the time of all this, you figure out how to re-coupe the $300 - from A) Working more hours B) Try to flip something off ebay thats selling to equal $300

But eventually you`ll gain it back over time.