The ones I have used can get to lager temps okay, they just don;t hold those temps very consistently.
I don;t know of any lager yeasts that work well below 45*F but, I don't know all the yeast strains either. 60*F seems to be the bottom end for most of the Ale yeasts I have used but, I am sure there are some that can handle lower.
Consider using a refrigerator with a temp controller. You'll be able to set whatever temps you want that way. They're usually about $60, google: johnson a419
I ferment my lagers around 50 degrees. If your lager is too cold and isn't fermenting very well then put it up to room temperature for a day or so. My lagers have been doing fine as low as 45 degrees though.
I ferment my ales and "room temperature" which is usually 65 degrees. For ales that I want more of the fruity esters I brew in the summer time when the house is 70 ish....