In the family reunification process both the German embassy in Conakry and the immigration authority in Bremen are involved in processing the application. If your wife has received a form about the application, then it is a good sign that the application has at least proceeded from the first step (embassy) to the second step (immigration authority). The immigration authority will examine the case from their side and if everything is in order, they will communicate their approval to the embassy.
If the immigration authority gives their approval, then the embassy will issue you with a visa. Unfortunately, I cannot say how long it will still take. You can make inquiries with the embassy but in my experience, they most often just ask you to wait.