In the configuration, under the tab "files" the height of your thumbnails is set to 200px. You should set it to something lower like 50px and then delete the content thumbnail folder in the "upload folder" via FTP so that the system can regenerate the thumbnails. That will greatly reduce the height of each item box.
Then, you can also increase the margin of your boxes to 35px. For that, go to Display->Content modules and edit the module with the id 60. There you will have the margin option on the bottom right corner.