General consensus is call out the Law.
Of course, last time I did that I got near arrested for "tresspassing" (even tho I never set foot on the property) and told I would be arrested for theft if I took it back.
So, it's your call...and all depends on how decent your local cops are.
Me...I would TCB myself, but I would not advise anyone else to do so.
PS - Also, if you do get it back, check older posts dealing with moped theft for my suggestions on how to KEEP it from being stolen next time.