I've just went to BBY General Libary today and asked about their room. The lady told me it's free to rent, they provide chair and tables. But it's only rent to non-profit groups. And weekday evenings only.
Sorry, I'm mostly only available on Sat (or weekday evenings). How about June 5? if not June 5, then we can go for some weekday nights and book a room at Metro library as suggested by strawberry muimui