Maybe you can change this period manually in google-analytics-top-posts-widget.php in this part of code:
`$defaults = array(
‘post_id’ => get_the_ID(),
‘start_date’ => date( ‘Y-m-d’, time() – ( DAY_IN_SECONDS * 30 ) ),
‘end_date’ => date( ‘Y-m-d’ ),
);
I changed nuber 30 and it is working in my case.