man, thats bit costly...i dont know for sure the price for the W210 Tranny Sensor but the W208 CLK Tanny sensor runs about $450approx(a bit more i think--I hope not for a W210!)....i know that its a Plug and Play unit under the center console....Good Luck
I have just recently done this myself.... And they pay those MB engineers all that money to align the drink holder with the gear shifter.....
There is a small over ride switch at the bottom of the gear shifter.... Its a little flap.. I happened to use a key to my old Ford pickup, but I think any lengthy object will work. Once you hit the switch the shifter will come out of park into drive, but the car will only stay in first. Hopefully that is all that is necessary to get to your MB repair site or home.
Mine cost me in upwards of 700.00 for my 2000 e320