iPhoto - Calendar question

Quick question regarding the calendar within iPhoto. I started up a new calendar that I'll print towards the end of the year, but have had trouble figuring out how to add photos to the project after the project has been started.

For example, I started this project with photos within my 2009 smart album. All is well through August. I now brought in newer pictures to iPhoto and my 2009 smart album has additional photos - but these don't automatically appear in the project's thumbnail list of available photos. So my question is, how to I either refresh that list, or how do I add new photos to my existing project? Or, do I have to start the project just before I print (with all the photos at that time?)

Thanks!