Better way to associate ticket quantities with event dates?
If you want to continue down the road you are on now, having an event description node and separate event date nodes, I would recommend you take a look at the References module.

If you want to keep all information within one node for a given movie/event, perhaps take a look at the Field Collection module.  The article Create Multigroups in Drupal 7 using Field Collections may assist you to accomplish this.