Kölsch Stuck?

I brew up a version of JZ's Kölsch two weeks ago using WLP029, and it just now stopped bubbling - so I checked the SG at lunch, and it was at 1.020 - way above where it should finish - 1.009.

I'm thinking that if that is all the more it has dropped in two weeks it might be stuck.

I'm planning on leaving it for a few days, maybe a week, and checking it again. My temps are on the low end - basement is at about 60-deg and I set up a swamp cooler like BierMuncher's to help keep it low. Fermented at about 59-deg (I didn't run the fan, I didn't want the temps to get too low). I guess if it doesn't drop any more, I'll move it upstairs and see if a warmer spot will get it going....otherwise, maybe I should pitch more yeast? I have some Notty on hand - would that work, or should I get another vial of WLP029?

I have read that this can be a slow working yeast, especially at lower temps - but I have overshot and it is too low?

I used 6-pounds of Extra Light DME and partial-mashed 1/2-pound of Munich for an hour. I don't have my notes with me, but the math shows my OG should be about 1.042 - maybe as low as 1.040 if my mash efficiency sucked....

Raise the temp to 70 and swirl the fermenter.

Ok - so after a week at a warmer temp, the SG is still at 1.018 - still seems higher than it should be. Is it time to repitch, or just go with it as is? I'm worried that if I repitch something else (like the Notty I have on hand) that there won't be a sufficient colony to make a difference. I'm also worried that adding more WLP029 won't make a difference, seeing as that it has a HUGE population now and doesn't seem to want to work.

My previous post was wrong (I didn't have my notes) - OG was 1.050, so it looks like 64% attenuation. White Labs says to expect between 72-78% for WLP029. 72% would get me to 1.014. Is 4 points enough to worry about?

Is it possible that if my PM didn't go as well as it should (I'm still learning PMing), that I could have more unfermentables in the mix than would be expected from 1/2lb of Munich?