Customize a custom post type shortcode for Wordpress

I have a 'events' custom post type that was created for my wordpress site. It has many custom fields set up editable when creating a new entry. What I need is: - the option to have categories set up for the events custom post type - There are 6 different categories of events that I would like to create, so that I can assign events to a category. - create a new custom field for the events custom post type - insert a text box field instead that is simply labelled showtimes and the client can enter a custom text sentence here. - currently the shortcode [events daterange="current"] creates a feed of all events occurring today and in the future, eliminating past events, and organizing not on publication date, but on the event date entered in the custom post type. I would like to simply add a category selector to this shortcode so that it will create event lists of not all, but only a certain category... ie. [events daterange="current" category="astrotours"] - as well a recent posts widget extended plugin has been installed that has had a modification to have a checkbox "Sort by upcoming event date", for some reason this option is not working anymore, events in footer widget 1 where the plugin is installed are displaying by post published date.. It needs to look at all the event post types and select the next 3 upcoming events by event date. When you select it and save changes to the widget area, the checked option box, automatically reverts back to unchecked. I need this to be functioning again and to be able to select which of the event categories to be eligible for this field. there is already a category field set up here, but i need to ensure the new categories created for the events custom post type will appear here. Please see screencaps attached.