1) In the custom CSS box, add .two-columns-right #secondary {width: 20em;} or whatever number you want.

2) Custom CSS: .module-navlinks ul {font-size: large;}

3) You can replace the text with the icons, though I can't remember where the setting is right now.
For the links: .entry-management-links .tell_friend, .entry-management-links .mem_add, .entry-management-links .watch_comments {display: none;}