if you want plain text, why dont you simply copy/paste in Notepad ?
if you need the pics to be kept and transfered to Word, then you'll need Adobe Photoshop or Illustrator to open the PDF and convert the pictures files as JPEG files
i dont think you can directly convert a PDF into a TXT b/c a PDF is basically a Postscript file (the same file format used by printer in RAW mode)