2007 AT Yaris Disappoints me

[frankencar]

Okay...

So I bought a used 2007 Yaris, AT, superbasic (no power anything). My wife and I share it, and though we're both conservative drivers - her a bit more than me - we're getting only 28-32mpg, typically getting 30 mpg on a tank. Now at first, I was okay with this because that's exactly what the EPA rating was, and for essentially an economy car it worked pretty well for our needs. However, after seeing these forums...I know there's a difference with the MT, and some hypermilers out there, but I've even seen some much higher claims for the AT. Which leads me to believe that either I've got a lemon, or there are lots of people out there who are calculating their mpg wrong

The one thing that concerns me is where the AT shifts. I haven't paid attention to it in awhile because I like my loud music in the car, but it seems to shift into fourth around 45mph, so when on the freeway going 55-65, the engine sounds like it's running at an unhealthy rpm. Is that normal? It seriously sounds like it needs an OD to me...but honestly I know nothing about gas cars. Electric is my thing. Please help! I'd love to solve this before my roadtrip in April.