Under normal fermentation temperature circumstances for lagers, that should have finished fermenting long ago. It is most likely just CO2 coming ut of solution causing the airlock activity.
Bottle conditioning lagers can usually be done at room temp just like ales. There is some risk however, when using malt-based sugars for priming, to producing esters and other noticeable off-flavors from the carbonation fermentation. But if you use corn sugar/dextrose, room temp. should be fine for lagers. After 6 months of lagering though, you probably want to add a little yeast to the bottling bucket.