Kirkus is careful to keep their paid-for "reviews" separate from their real reviews. The way I understand it the paid-for "reviews" aren't even in the hard-copy version that the folks at libraries and bookstores subscribe to.
Anyway. Back to Xlibris. They're a notorious vanity press. Our thread on 'em is here: http://absolutewrite.com/forums/showthread.php?t=942
frosteeman, what you should do right now is forget this book. It's dead. Write a new, different, better book and send it to a real publisher.
Might as well talk about where reviews on covers, and blurbs, come from in the real world. (Note: Neither the author nor the publisher pays for reviews or blurbs.)
First, let's talk about blurbs. Those are the little things like, "The best book I've read this year!" -- Some Other Author that you see on book covers.
Where they come from: While the book is in production, the publisher prints up a bunch of Advance Reading Copies (ARCs) or Uncorrected Proofs. They paper the world with these. The blurb quotes usually come from authors who are: a) The author's friends, b) Other clients of the author's agent, c) Other authors published by the same publisher. What the other author gets: An ARC. Also, the promo value of having their name on the cover of your book. No money changes hands.
If you see quotes from reviews printed on the cover of the hardback, notice that those are usually from reviews of the author's previous book.
Remember those ARCs? This is all happening about six months before the book is due to be published. The ARCs get sent to every major reviewer. The publisher's publicity department handles this; it's at no cost to the author. So The New York Times, the Washington Post, Kirkus, Library Journal, Publishers Weekly, the Chicago Tribune, USA Today ... and anyone else who might be interested gets an advance copy. If your book deals with dog breeding, the specialized dog-breeding magazines will get ARCs. The idea is you want the reviews to hit the papers the week that the book is released. (It doesn't do any good for a review to be printed for a book that isn't available yet.) Any ARCs that are left over will get sent to book bloggers, and anyone else who wants one. Really, they send out a lot of 'em.
What happens to the reviews: If your book is a hardcover, and later gets a paperback release, the juiciest quotes go on the cover of the paperback.
If you get a really, really juicy quote, or win a major prize, the publisher might decide to reprint the dust jacket with the quote on it.
Suppose your book is a paperback original? In that case, the review quotes go on the cover of the second or subsequent printings.
Notice how much this costs the author: Zero.
Notice how much this costs the publisher: The cost of printing and mailing the ARCs (which is all budgeted when they decided to offer on the book).
Notice how much what Xlibris is doing resembles the real process: Not at all.