The best way to get association history on a single AP is to run a report.
Here's the steps I take to do this:
Find the AP, not it's name
Go to either the controller or the folder that has that AP
Select the modify devices wrench to get checkboxes
Then check only the AP that you're concerned with finding the history for
Choose the 'run report' option from below the list table
The options to get the data you're looking for are in the 'client session' report type
-you can also use just the portion you want from the custom - client session options
The two that most fit your description would be: sessions, session data by client, and summary
Note that report start and end need to cover the span of data maintained in the database.
The availability of this data is restricted by AMP Setup -> General tab -> Historical Data Retention box -> Client Association and Inactive Client categories.
Give this a try and let me know if it accomplishes what you're trying to get. Also, try the other options under 'Client Session' to find the format you desire.