The amount of history that you will be able to see is controlled by the LICENSE_ARCHIVE_PERIOD site parameter. By default, it is set to keep site connections and license usage information for 1 year. You will need to check to see if this parameter has been set and if it has changed.
Description: The period in days to purge old sessions records from SESSION_HISTORY table
Default value: 365
Min value: -1
Max value: 9223372036854775807
Introduced in release: QC 10.00
Introduced in patch: GA
There are no reports that are built-in to ALM for tracking user connections. The user and connection information are stored in the Site Admin database not within the projects where the reporting features of ALM can reach them. There is the Site Analysis tab within the Site Admin that does give you a graph of conncurrent usage of the licenses for ALM. Additional information for this can be found on page 180 and 181 of the administrator guide.
If you are looking for on user logins that information that you would be looking for would be in the SESSIONS_HISTORY table within the Site Admin database (qcsiteadmin_db by default). This table would store information such as Login and logout times, the domain and project logged into, and the type of connection (ex the ALM client or OTA API).
You could query this information and export it to Excel and then create a report in MS Excel using the raw data or if you are familiar with Excel VBA and APIs you could use the Site Admin API to create a report in Excel.
Link to the Site Admin API...