2006 Acura TL Servicing

My dealer is telling me that I need to change my brake, steering and transmission fluid on my car - cost is about $400. The car is 4 years old and just under 50,000 miles while driving a mix of highway and city, but under no extreme conditions. In my years of going there they tell everyone that is in for normal service or maintenance that something else must be done on their car. Do any of these items need to be done now or are they just upselling me like they always seem to try. And if they need done, can I get these done at a non-acura service shop or should I get them done there?