Quoted from Razorbak86:
The books haven't even been finished. The TV series is a LONG way from being finished.
Well, it's going to get interesting how they handle things going forward. Apparently they're skipping a good chunk of the fourth book (which George Martin should have done as well) and are actually doing material from the last book released--the fifth--this season. After next season, they're all caught up with the last two books not released yet. So it's not long before they lap the books...don't know what'll happen after that.