Lisa,
You may currently have the web part retrieve both new and modified (changed) list items...just by selecting Modified Items in the Item Type option from the Scope, Results & Cache ToolPart. SharePoint writes a modified date value, which is the same date and time entered in the created date field, when it creates a new list item. So, if you configure the web part to retrieve modified list items, it will also include new list items as well. If you have not done so already, I would suggest you also enable the New! icon for new records so users will be able to distinguish the new records from modified records.