You can start raising the temp after 72 hours, basically 2 degrees a day until you get to 58. I know you say you pitched enough yeast and I don't mean to sound like second guessing you, but when I make a big lager .... really big, like 1.080 or so, I can have the fermentation wrapped up in 2 weeks. For big lagers, it is best to start with a lower gravity beer and use that slurry. Or use dry yeast - I like S-189. Good luck with this one. Raise that temp up and it should be fine.