We'll assume you don't have extended motorplan of course- and good on you:thumbs:
Your owners manual should have come with a schedule telling you what service items to be worked on at what mileage or period/time. If you don't have that info, a simple google search for your car's service schedule should be helpful.
BMW agents cost the earth, a total rip off in my opinion. I don't know how they justify such extortionate charges. I wouldn't just trust any RMI approved agent either when it comes to specialist work. Find a workshop that specialises in BMW service/repairs in your area. Every city has one or more, and there you will find technicians who often have worked for main BMW dealers before so they know their way around your car's unique specs. I would only trust RMI people with specific work I've asked them to do and give specific instructions. I would not park my car there and ask for a "service". You don't know what quality level parts they're putting in your car- could be some cheap pirate rubbish that will cause problems later, and you don't know what oils, lubricants they're pouring into your engine etc. I don't always use genuine BMW parts cos they're not always necessary but its crucial that you use reputable branded aftermarket parts from the best automotive companies that meet or exceed the manufacturers specifications in your BMW if you want it to perform optimally and remain reliable.