Read Meta-Tags out of EPUB-Files

[Eternico]

Good day mates,

I recently opted for a Sony PRS-650 and I'd like to manage my library with calibre. Now, I suddently found on the internet a collection of 5500 ePub files, with are all copyright free (of course ). My problem is, that they are all free of any meta information when imported into Calibre. Searching in the ePub-archives, I found that the original HTML-files had meta information such as...

  <title>Johann Christoph Gottsched: Sterbender Cato</title>
  <meta content="tragedy" name="type" />
  <meta content="Sterbender Cato" name="booktitle" />
  <meta content="Johann Christoph Gottsched" name="author" />
  <meta content="1997" name="year" />
  <meta content="Philipp Reclam jun." name="publisher" />
  <meta content="Stuttgart" name="address" />
  <meta content="3-15-002097-2" name="isbn" />
  <meta content="Sterbender Cato" name="title" />
  <meta content="3" name="pages" />
  <meta content="1732" name="firstpub" />

...but calibre doesn't get this information. Now my question is: is there a way to let go all the 5500 book (I own pure HTML-versions of them too, if this helps) through a script that reads out this meta content and makes it suitable for Calibre?

Sorry for my crappy English and thanks in advance