Help with all-grain lager- FG high

I brewed my 1st all-grain lager about 6 weeks ago and I thought I was ready to bottle, but my FG seems high. I used all malted barley (mostly Dingeman's Pilsen... no adjuncts) and pitched a starter (WLP 830). My OG was higher than expected (1.060). It fermented for 2 weeks at 50 F and I took an SG which was 1.020 and airlock activity was 2-3 per minute. Then it had a 24-48 hr diacytel rest, and lagered at 36 F for 4 weeks. I was preparing to bottle tomorrow and took an SG tonight... it was 1.017. It's lightly carbonated right out of the carboy and tastes good, but seems slightly sweet. I'm new to homebrewing, so I'm not sure what should and shouldn't be as far as tastes go before bottling. Is this FG high? Should I lager longer? Do I need to change temperatures/agitate it to re-suspend yeast to get it to ferment more? Or should I add boiled/cooled water to the bottling bucket to lower the gravity (is there a calculation for this)? Advice is greatly appreciated.

Mensch, my experience with lagers is limited to only a few batches, but I've found lager yeast to be SLOW. Two weeks doesn't seem long enough to me. I've had fermentaions go for for four to six weeks (eight weeks for a doubble bock one time) , usually at 45 deg. BTW, I only rack the beer into a secondary if I'm doing a lager... because of the long exposure to dormant yeast, and that's just out of a fear of autolysis (How do you spell that?). -p

Oh, I didn't provide advice, which is what you asked for... I'm sure there are others out there with more experience but here's what I'd do: I'd agitate that beer a little bit, rack it into a sanitized fermenter, and let it warm back up to 45 or so and let it sit. It'll be great. -p

Thanks for your help Perry, the only problem is I already racked to a secondary when I lagered. Two weeks in the primary seemed like enough from all that I read and I thought my SG was OK (1.020) to rack to secondary/lagering. Maybe I just need to lager it longer, but if it only came down 3 points in 4 weeks, how long will it take to come down more!?

If the SG is still dropping then there's yeast in there doing it's job. Just leave it be for a while, check your gravity in a month and see if it's dropped anymore. Also, make sure you're correcting for temperature, the hydrometer is calibrated for 60F, other temperatures will give you incorrect readings.