I just got 2 new Britax Frontier carseats. They are fantastic!! I got them for $279 and they sell them at Target.com. Here are the weight/height requirements/restrictions:
For Children 25-80 lbs. with Harness, 40-100 lbs. as Booster; For Heights 42-60" as Booster
After doing some research I have the answer on my own question :).
The best buy at this moment is on the Britax Regent which sells on a closeout for $159 and/or $165. It goes up to 80 lbs. So if money is the issue, well...this is as good of a deal as it can be...It got really high reviews for safety.
My girls are both in the Graco Nautilus, which I think Melanie recommended to me here. They were $150 at Walmart, and they hold a child in the harness to 65lbs. Then it converts to a high-back and then a backless booster, up to 100lbs. I can't remember the heights on them, but they were pretty generous. We have been really happy with them, and have no complaints at all.
