Right clicking on a Mac with a singl ...

My Mac laptop only has one button on the mousel.  I have no right click, and I do not have the newer macbooks where you can assign one corner as the 'right-click' corner.  My laptop is barely two years old. 
How can I 'get more info' when playing HA on my Mac through steam?  There is no question mark button, and I've tried every combination of buttons I could think of that usually doubles as a right click on other games/apps.
 
Thanks!