I'm assuming you don't have the full, payware, version of Acrobat otherwise the task would be easy. With the free reader it depends on the version you are using as they changed the menus over the numerous versions.
Usually you have a 'hand' tool which allow you to move page by page but what you want to find is the 'text' tool which should look like a capital 'I'. Sometimes this is visible on the tool bar other times you have to find it in one of the menu options depending on version. Once you have the 'text' tool active you can 'drag' over the text you require, select 'copy' and then you can 'paste' that info into any program you like.