1. Make friends with au pairs from other countries. You will be forced to speak English together and you will have the side benefit of learning about their cultures. We even have a few native  English-speaking au pairs in our cluster. In addition to being really cool ladies, speaking with them would be a great way to improve your English!
2. Check out the  International Club of DC  for great activities and opportunities to interact.
3. Check out Meet Up  to find activity groups for any interest.  There are groups getting together for sports, book clubs and even ones to improve their English.
4. Look for activities and classes through the local Parks & Recreation Departments. These will not count toward your education requirement, but they are a great way to try something new and meet people.   
5. Look for clubs and activities through your community college.