To determine which version of Outlook you have, start Outlook.  If your main Outlook window looks similar to the one below, then click on File...Help.  The version number (including whether you have 32-bit or 64-bit Office installed) is on the right:



Note that many people make the mistake of assuming that Outlook (and really all of Microsoft Office) is 64-bit if the operating system is 64-bit. However 32-bit applications run perfectly well under 64-bit operating systems.

If your main Outlook window looks similar to the one below, then click on Help, then About Microsoft Outlook in the menu: