What is the temp you are fermenting at?
Did you use a yeast starter? What Size? Any idea how old was the yeast vial was?
I have some experience with the yeast, and what you are describing is what I have experienced when I ferment at about 45F with the yeast. (after a yeast starter) What I found was that it took FOREVER to take off, and then when it did, it just kind of chugged slowly. It took about 5 days to see any real drop in the gravity, then it took a full 22 days to complete, and then it was at 1.018 (started 1.055), which is a bit higher than normal for me.
My suspicion is that you may have under pitched and are running at a low temp. However, if you are seeing a few bubbles a minute, I would not change much at this point, and would just ride it out. The next batch, I would possibly pitch a bit more yeast, or raise the fermentation temp a couple degrees if that seems appropriate.
Good luck with the lager, I started down the lager path two years ago and while they take quite a bit more time to produce than Ales, I have loved the end results!