About Intergration script into jamroom
Using Jamroom
If you can integrate the chatroom as a custom module, its all still do-able with jrFoxyCart, quotas and template modification, as described above. After subscription, users would be moved to a quota with the chatroom module enabled, and template mods. would also have to detect the day of week as well as the users' quota.
SteveX has a chat module here - http://www.jamroom.net/ultrajam/networkmarket/108/together-mpl - Have you checked that out?