Chinese touristic/guest(?) type for a Russian citizen living in the Czech Republic

Hi, I'm a Russian citizen living in the Czech Republic. I'd like to visit China to see my close friend, and so I am planning to stay with him for the whole duration of my stay. I believe in this case I don't have to book a hotel, do I? What can he provide as a confirmation of accommodation? Can I apply for Chinese visa right from the Czech Republic or do I have to go to Russia/Russian embassy? I've also heard one has to provide some kind of personal letter/motivation letter or something of this kind, is this correct? If so, what exactly should be in it? And, finally, where do I get the travel insurance for my trip?
Or are there any touristic agencies over there in China, which can provide me with the invitation and all the paperwork?
Thanks in advance,
Irina