Im not sure of the cost of valet. For some reason Im thinking it is now $9 a day but I could be wrong. We own DVC so valet is free.
$2 per each way is general I think, at least that is what we always try to pay.
And yes, you can call from your room and unless they are very busy, your car will be waiting for you. I have found that sometimes, you can just walk up to the valet desk outside, and they will have you ready to go within a couple of mins. I like to do this so I can personally hand the valet person their tip as they get out of the vehicle.
I have to say, of all the places we have valet parked at WDW, WL is the most efficient and friendly. I told one of the fellows working their one night this same comment and he told me that WL had won the best valets on property award for like six straight yrs. And it shows!
I will say that the parking lot isnt that far from the main Lodge area so if you get tired of forking over the bucks for it, that walk isnt that bad. I probably wouldnt use valet as frequently if it werent for us getting it free.
At any rate , enjoy! We too will be there in Dec staying at the villas.
I do expect a full report on that..and the entire menu when you return, first thing! 
for a wonderful vacation!
