To learn more about what's happening on the International Space Station at any given time, check out NASA's frequently-updated ISS blog or their page about the research and development work happening on ISS.
Depends on your body type and metabolism and your routine. But usually it takes around 3 to 4 weeks for visible results. For me it took me a couple of months to actually see any progress visually.
You can gradually return to normal activities and exercise from 4 weeks post surgery being guided by your body and how you are feeling. Cross fit style activity and intensive training can start after 6 weeks and any contact sports should be avoided for at least 3 months.