Need Convertible Carseat recommendation?

[gibsontrio]

Hello mommies and daddies! I have a Britax Marathon carseat that I used for my DD5. I went to clean it today for my dd who is 4mths old (20lbs and HEAVY in her infant seat) and I noticed the strap on the marathon is torn. I dont feel comfortable buying new straps since I only used that carseat for a year (thank goodness I flipped it over and inspected it !) So I need recommendations for a convertible carseat It needs to be able to rear face since my dd is only 4mths and I prefer NOT Britax to buy another Britax.
We are moving to Germany in 6 mths so I need it to be FAA certified to fly. Any recommendations??