What Reader version do you have?
I don't see such a toolbar at the bottome (in 10.1.2), but just the menu bar and tool bar on top. These can be toggled using F9 and F8 (on Windows).
Are you referring to the heads-up display that appears at the bottom of a PDF when viewing it in a browser? This is referred to as Read mode and is the default viewing mode when you open a PDF in a web browser. To access your toolbars, simply click on the trefoil icon (right most icon) in the heads-up display.