It must be refilled via the trans dipstick. If you have the hood of your car open, and you are looking at the engine from the front of the car, it's at the end of the engine block, by the firewall, on the left corner. I believe it is either a black or red round plastic cap. It is probably sealed and will need to be broken. Be sure, if you do do this yourself, that you get the special transmission fluid from Mercedes-Benz!!! Do not put anything else in there. Your transmission is very sensitive to fine particles, fluid amount, and the type of. If I were you though, I would strongly recommend you have it towed to the dealer and have them do it for you... It shouldn't be very much money.... but considering a new trans in your car would run you about $4,000 dollars, I would have it done by the dealer!!
Good luck with whatever you do.
