There is a bug with the display of available data on the Audit Trail reporting page that should be addressed in the next version of Audit Trail. As for not having the most recent audit data in the actual report, you may be running into the issue mentioned and fixed in KB 1013659.

Audit reports pulling from a Microsoft SQL Server 2012 database did not automatically update with new data without either restarting the Audit Reporting service or first changing the date range on the report. This issue is now resolved. (125202)

One thing to note is that we have seen this occur not only in SQL 2012 though. Note that you should already be using Audit Trail 9.2.1 prior to applying this fix if you choose to do so. The workaround is to go into the Audit Trail Configuration page and drop the current date range and then add it back as that should force Audit Trail to reload the data into the database.