From Borno (NE Nigeria) to the Kawar Oasis
 

I plan a trip to the Kawar Oasis in August. Coming from Maiduguri, I plan to travel via Diffa, Nguigmi, Afadem, to Fachi and Bilma etc. I wonder how far public transport is available. I travel alone (without own vehicle) and have allocated about 1 week to reach Bilma and one week to go back, to Kano. Are there traders going on Lorries which I can ask to give me a lift?
I also tried to identify a Niger embassy in the UK, but without any sucess - is there one? Does anyone know whether German citizens need a visa for Niger?