As far as I know, to get the name of the player character, you need SKSE and then this function:
http://www.creationkit.com/GetName_-_Form
However, what I think you then need is TEXT REPLACEMENT: http://www.creationkit.com/Text_Replacement ... but sadly I don't think that will work with Dialogue.
So, you could write the player name in a book, name a sword or peice of armour after them, even have their name in a Quest Objective or similar ... but I do not believe you can add it to Dialogue
(someone super will now wander into this topic and tell you I am chatting nonsense ... you just watch!
)