I couldn't tell ya where to buy a stock jack besides a BMW dealership, but I know they will charge you up the ass. The stock jack is pretty bad anyway...I would hunt around for a different one.
Heh, "serviced," is a pretty broad term. Usually it means (in my experience) replacing all the fluids, any messed up belts, new air filter, change out the oil checking all those hoses, checking shocks and springs, making sure the clutch looks ok, checking for cracks in fans etc etc. Although I'm no expert in the field, I will tell you that this Wednesday I am getting my first "full service" (bought the car with 70k miles on it, it has 87 now, and I have NO idea if the previous owner serviced it, the people who are taking care of it for me said it didn't look like it). My full service is going to cost around $700, so I am fairly certain the work is quite extensive.
Sorry I couldn't be of more help, but when I get the invoice for all the work and the final price, I will be sure to list all the things they did. Good luck
Just FYI - I am switching to synthetic oil @ 87k miles. I tell ya how it turns out.