If you are considering a career in any of the following subjects then its important that you follow your BA with a MA,because that will give you better career opportunities as compared to a BA.
You can consider taking up a course in foreign language, which will help you in taking up job opportunities in foreign embassies with your exposure to public administration and political science.
You can consider taking up a course in social work, with you background of public administration and further consider working with a NGOs. For this you can even take up a masters in public administration or an MBA. TO go a step further you can take up a career in civil services too.
Hope this helps.