Make the deal at some Motorbike Shop. They have all documents there and will charge you for the service only a few bucks. Only thing you have to care yourself about, it's the prove of residence from Immigration. That's a 10 minutes-job only.
nope, there's a TR available, multi entry and valid 6 month. That means, if you re-enter on last day of validity, you may stay 9 months including the final extension.