if you're wanting to buy the tickets, you can't. Tickets have been sold out for maybe a month. But, you can prob check ebay. Maybe some people are selling them for over priced there if you really want to go. But do you really want to risk your hearing?
There will be so many fangirls there. The room fits a certain amount of people, but I'm sure the fangirls will pack in. Plus they'll be screaming, and if you don't get a good seat, you won't be able to hear anything. If you get annoyed easily, especially with the fangirls, I suggest just watch a live streaming video if they have them online.