wow, $240 in labor???? thats crazy i just brought a alternator and they wanted $100 to install it and i did it myself instead.....if your handy it shouldn't be hard, find out the piece "they said" you needed and try n find it cheaper then do it yourself, takin off your door panel shouldn't take longer then 5 mins. Get a haynes/helms manual if your not sure or search the web on installation
.......if you got $$$ like that, then go ahead n pay them to do it, me personally i'd do it myself....good luck