Lager fermentation tends to take longer, but it's because of the temperature, not the fact that it's lager yeast.
To me it looks like you are pitching nowhere near enough yeast to ferment at that temperature. If you pitch one package of 2124 with a 125ml starter at 45 degrees, you are asking to get underattenuated. Use the pitching rate calculator at
www.mrmalty.com to find out how big your starter should be; you are likely looking at 4 litres or more for a beer that big depending on when your Wyeast is manufactured and whether you are using a stir plate for your starter. Given how big your starter will need to be, you will want to chill and decant it once it has fermented out (you can make it at room temp if you're pressed for time).
There is no point doing a 3-4 week primary. Instead, do a diacetyl rest by raising the temperature of your beer above 60 degrees (room temperature is fine) when you are 8 gravity points or so above target FG (you can determine your FG with a forced fermentation test or ballpark it by looking at your OG and attenuation range for your yeast). I like the 2124 (I use the Saflager dry yeast equivalent a lot) and think that even in the mid-40s you will be looking at a d-rest in 10 days or less. You want the d-rest to occur during the last part of active fermentation. For a big beer like your planned Oktoberfest I'd be thinking about a d-rest in the high 1.020's. Once your temp is raised, leave it there anywhere from a few days to a week, then rack to a secondary for lagering (make sure fermentation is complete).
One last observation is that your grain bill is pretty big; what is your target OG? An Oktoberfest OG should be 1.050 to 1.057.
Good luck!
Lager yeast question
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