[DREAM2]

I went to change my oil for the first time, the dealer has been doing it since I have lifetime free oil changes. They do not offer synthetic so at 15,000 miles I decided to start doing it myself.
I have no idea what they used to tighten the drain plug on with or the oil filter itself, but neither will come off. I almost stripped the drain plug trying to get it off. I'm taking it to a mechanic friend that has a lift and some air tools to try and get them off.
I no the drain plug is 13mm, but does anyone know the thread size and length? Or better yet where I can pick up a new one?