One of the brave things about Doctor Who stories generally is the lack of officially stamped layers of canon (it's a story about a time traveler so the past can change and snap back). You can if you wish to, even tie the Cushing films (Barbara and Ian sold their story to a film company) in both Shadas and the Unbound audios.
A key point of contention is the novels, audios and television series point to a terrible event on Gallifrey of which the Eighth Doctor is a key player.
You can either read them as three totally unconnected events happening in separate story branches, separate events happening one after another or the same events altered by the nature of the events.
So I wouldn't get to hung up on where the books, television, comics and audios fit in relationship with each other.
To enjoy each media's take on the character it's best to read or listen to them in order but you will very rarely get a comic character name dropped in an audio or an event in a novel turn up in a comic.
It's a time of chaos.
In some ways the Eighth Doctor has the most interesting journey of them all, not bad for a guy who only got one television story.
Matt's journey starts on April 3rd in Britain and April 17th on BBC America.