Thanks for the interest. This book was originally written in Hungarian, because some of the topics were not discussed in our literature before. Since there are a few great GR textbooks for Hungarian universities already, I was focusing on the math, and neglected long explanations in the text...
I wrote a general relativity book myself, it can be downloaded for free here: http://valek.webs.com/
Take a look people, tell me if it is any good. If something is blurry or wrong, I will try to correct it, so come back often, to check for updates.