[kezoo]

IMO, a 2.5 year old should NOT be in a booster. We talked to the people at our local children's shop (they are VERY knowledgeable) and their comment was that a 5-pt seat is much safer than a booster, and a booster shouldn't even be considered until about 4 years old. I don't think a Roundabout will last your ODD until she is 5, as it goes to 40lbs max, and there is also a height max. My ds was 29lbs when he turned 2 and now at 3.5, he's close to 40lbs. I would suggest giving the Roundabout to your YDD and getting either a Marathon or another Britax convertible seat for your ODD. We recently bought a 2nd Marathon and I found some great deals on the web for last year's fabrics and free shipping.