How expensive is Abuja?

Hi all. I'm new to this forum. I plan to move to Abuja in a couple of months to take up position with an NGO. I've heard many people say that Abuja is a great city, but very expensive for ex pats. How does it compare to the cost of living in other African capital cities? Does anyone know where I can find specific information on the cost of housing, security, schools, food, and all the little things that you don't usually think about before it's too late...?

Thanks

Richard