Itimpi and Dwanthny thanks a lot guys.You explained well how I can get my metadata changed without actually having to do EPUB -> EPUB.
And that's what I exactly did just now.Used "Save to disk" for all my books, deleted all of them inside Calibre and imported the ones I saved...and Voila!
all of them have MY matadata and layout inside same....I think from now on am gonna do the same process each time I add a book...
Thanks again.