That's scary! That's why I'll never take or buy a hand-me-down car seat. Even if it's from someone you trust, you just never know.
Graco makes great travel systems. They have lightweight & full size ones. We got the Alano system (it's lightweight) for Christian and plan on using it with the next baby. With the Alano, the car seat only goes to 22 lbs (it's a SnugRide). Graco now has a couple of seats that go to 30lbs (SafeSeat) and 32lbs (SnugRide32), so you may want to look into the travel systems that include higher weight limit seats so you can get more use out of them for your money.
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You can also check out the Chicco Cortina travel system. I would still love to have one of these for the new baby but I can't justify buying a brand new (& more expensive) travel system when we have one that's in perfect condition. If you do look into these, make sure it's the Cortina KeyFit 30 Travel System (car seat goes to 30lbs) other than the 22lb one. You will get more use out of the car seat.
Chicco USA - 30lb Cortina Travel System - Romantic