Since no one has replied to you in a while, I have heard that $650 is about the median for that service. You can search the forums to see what all it entails, but it is fairly detailed for a DIY'er.
It depends on you if you want to do it or not (youself or stealer), but even the worst of bimmers last for 150K+miles.
If your previous owner was as religious as you imply, then I say drive the damn thing. How many miles do you have?
As for the cooling system - every 2 years, especially when older. Use ONLY BMW blue coolant.
AT fluid - I think these are 'sealed for life' transmissions, meaning you can't change the fluid. I have a manual, so I can change mine. There are people on this board that will tell you you can change it, but if you have 100K+miles on it, just leave it. If you break into it now, you're bound to screw something up.
The brake system, I believe, is to be flushed every 2 years as well.
Need a new sig...
A BMW is for the soul, a Chevy is for groceries...