I guess the first thing to do would be to give your best guess as to the most likely reason it is stuck. Is this AG or extract/PM? I love topics like this because it helps me (and others) learn the reasons for things going wrong like this. Here's a list of what I believe to be the possible reasons for stuck gravities. Feel free to add to this list so others can learn. Some of these won't apply to your situation but narrowing it down might tell you if there is anything you can do about it.
- High mash temps (whether intentional or not)
- High proportion of less fermentable malts (cara-pils, crystals, etc.)
- Lack of adequate amounts of yeast nutrients (typically for extract brews only)
- Low fermentation temps for the yeast strain
What did I miss?
If it's one of the first two, there isn't much you can do about it (adding enzymes gives unpredictable results will probably get it too dry), but keep in mind with a lager, you'll probably lose a point or two of gravity during lagering since the lager yeasts are cleaning up some of sugars that aren't fermented in the primary phase. You could also lose a point or two by diluting it with water at the time of kegging/bottling at the expense of ABV and IBUs, but if you keep it minimal, you won't notice much of a difference. If it's any of the others, you can get it going again by adding yeast (which you've done), stirring up the yeast, adding nutrients, etc.