A good way to meet local runners is to participate in a parkrun. Alstervorland parkrun is in this area.
If you need an open track in Rotherbaum; Jahnkampfbahn is marked as open to the public.
Another option not to far away is 400m synthetic track.
Running in a new city in the winter time can be tricky. Bad weather and darkness makes it hard to find good places to run.
Außenalster is suitable for running year round and has electic lighting.
Jahnkampfbahn also has lighting.
Außenalster has a soft surface for those who like to avoid the asphalt and concrete.