Abuja to Windhoek travel advise?

Hello, has anyone got advice on flying from Abuja Nigeria to Windhoek Namibia?? We are just starting a business venture and are finding little in direct routing. Advice as to the best route/airline would be appreciated.

Also, is it possible to buy the ticket once in Africa (my initial belief is that my Visa requirement will demand that leg be bought before I leave North America to show I have a flight leaving Nigeria itself). Is there a particular travel agent in country you can recommend for future or do you find internet bookings best as in North America.

Any advice is appreciated, we are only going to be in Windhoek a short while before stopping around RSA to visit colleagues, so even hotels etc. are much appreciated for the Windhoek area.

Lyle