Hi! Sorry to take so long posting back...we just got back from a trip to San Antonio in the popup. I love that thing, but with three growing kids, I'm seriously considering upgrading to a trailer with slideouts and a bunkhouse!
Anyway, to answer your question, I think her carseat is a Graco Turbo Booster. We bought it at either Target or Toys R Us about a year ago, and hers has princess purple trim, but it comes in lots of different styles. What I like about it is that the back is hinged to the bottom, so I can recline her chair and with the decent-sized "wings" near her head, it supports her head while she sleeps. Here's a link to one--in a much more guy-worthy style--at
amazon:
http://www.amazon.com/Graco-Turbo-B...2/104-7767090-0165545?ie=UTF8&s=baby-products. If you can't get that to work, I just went to amazon and typed in "carseat booster" in the search field for baby products.
I was a kid back in the pre-carseat days, too. I clearly remember my parents taking me from Ohio to Florida when I was 4, and I rode on the floor of the backseat almost the whole way. I couldn't believe it when my mom said she used to just carry me in her arms while my dad drove when I was a baby! It's amazing how things change in a generation.
Have a great trip!
Sue in TX