Do a bit of investigating online to see what fields of study are offered by your local institutions of higher learning. Determine whether each school has a Political Science department; most schools do confer this degree, so you should not have a problem.
Compile a list of schools to focus on. Visit the listed universities and colleges in your town, but call ahead first. Connect with the Political Science department heads from each school. These are usually the people who know best where the collections are kept. Theses will frequently be found in binders on shelves dating back for decades. Ask about the topic of African Politics specifically, since at least a few authors will have written about the subject in the past. Try to check out the theses you find from the schools if they will let you take them home. You will need ample time to read all of the content, and you might want to make notes to help guide your future studies.
Call and visit your local research libraries to ask about the topics available. Librarians there should be able to search their collections on your behalf and let you know if they have any written works on African Politics. Visit the libraries in person to check out the research papers if they are on offer.
Peruse online academic databases and journals, like JSTOR, Oxford Journals and Google Scholar. Use pertinent search terms and tick the appropriate boxes when presented with subtopics. If you don't require an original draft of a physical thesis paper in your hands, this is perhaps the easiest solution to finding the information you're looking to collect, without all the footwork involved in traditional academic research.