How much should I ask?

[ffbigbang]

:hi:

I have a question. I am the owner of the site www.thesecret.it
The book and the movie "The Secret" by Rhonda Byrne will be published in Italy in october.
A book publisher contacted me asking to sell them my site.
How much do you think I should ask them, considering that "The Secret" is a worldwide business and has sold for millions in USA?

Thank You for your suggestions!