Definitely try the olive oil and shea butter and see how it works. Also you might want to deep condition with an all natural product. My hair used to like those products you mentioned, but after a while it got sick of them so I've switched to using only all-natural products. You can try some products from the sheamoisture line. As a deep conditioner I highly recommend the Purification Masque:
^Wish that picture wasn't so big -_-, but you get the idea.
Bentonite clay is also good for getting rid of any build up on your hair if that might be preventing any moisture from getting into the hair shaft. I have a whole list of other things you can try, but just see how some of these suggestions work and give us a ring if you still need help.
Good luck and tell us how it works!
Mostly 3c and lovin' my curls
This is not a fashion trend, it's not a statement, it's pride for who we are and what we look like. And that is where our true beauty shines.