What I've heard is that 3-8 weeks is normal, with 6 being around the usual. Keep in mind that depending on how difficult the labor was, whether they had to cut anything, etc, she may still be in some pain even after the bleeding stops.
Something that can make things even more difficult is that at times, some wives may feel the difficulty of a long separation, and then you have feelings of wanting to help her thrown into the mix.
The key is that you can do this, you both can, you will. You'll be fine.