So far I have not found any recording or whatever in Japanese, but the Chinese fan who attended the meeting on 2013.1.3 and originally reported the news above have translated many of Gosho's answers in one of his/her Weibo (微博) blog entries. He/she saved everything written as a very long image file rather than typing it out (possibly because there's a character limit). And since this is based on this person's memory only, he/she said that not every detail can be correct. And of course it means that not every Q&A can be remembered here.
User/poster: Y大蟹酥Y
Original link to the Weibo blog: http://weibo.com/u/1986450982
UNFORTUNATELY, to be able to gain access to Weibo, you must have an account, which I don't think anyone here does. The image and my crappy English translation can be viewed in the spoiler boxes below (I cropped it into 7 parts).
DISCLAIMER: I don't own this image. Image source is on the bottom right corner of the last part. And just so you know, I don't even think I have the permission to post this thing, even though it seems to be meant for public view -__-"" ...