Technically, the meanings are correct, but I think the nuance is tricky here.
Depends on the context.
If I'm just simply asking intent, and wanted to say "You're gonna go to Comiket aren't you?" I would say （name of person)はコミケットに行くんですよね。
Or simply asking I would ask コミケットに行く？(better to state the time though 来週とか)
I would use 行くつもりですね if they just expressed that they are going and I am quipping about their intent to go i.e. "Oh, so you're going are you?". Very different nuance.
As far as the response goes, they wouldn't use あの as あの in this case would point to a week that wasn't mentioned in the conversation but is secretly know by both parties.
In this case その would be appriorpiate. However, I don't think someone would naturally need to say 'that week' since there is no week asked or given in the context of the conversation, but if there was context it would be その週は仕事があります。without the よ.
よ is used to to appeal to someone when they don't know something or you really want to drive something across to them. Otherwise you don't need it.