In need of advice on maintenance on my 2.5 yr old Yaris Sedan

[Yari-Chan]

I went in to the dealer to get an oil change for $24 and left the dealer 3 hours later with $691 less in my wallet. I feel horrible. I think I was being an idiot and just got cleaned out. Now I'm pissed and here to do some research and get some good advice from more knowledgeable folks at Yaris World. Next time I won't be so stupid.

Here's the service they did:
-First they said I was overdue for my 30,000 mi. service. I have 35,000 miles now. That would have cost me around $450 alone.
-Then they said I needed fuel injection system service. The service consultant explained it by saying that when I put gas in my car there is sediment that collects over time and instead of the gas spraying, it jets out like a sand blaster and would be harmful to the fuel injectors that I will be replacing with my 30K tune-up. He said they had told me about this the last time I was in so now it's worse.
-Then I was told that I needed to take care of my power steering system. I think it is a replacement of the fluids or something. This also was told to me last time I was in. I don't remember them saying anything about either one.

Does this sound right to anyone or did I get taken like I think I did?

What is absolutely necessary for maintenance of a Yaris sedan?

I would greatly appreciate some input from others.

Thanks!