You can get generic newborn inserts for carseats from BabyRoad - I got mine in the Meville store on Leach Highway but I know that there are other stores around. They are expensive - I paid $62 for mine and I kind of regret it because I'm going to hire a baby capsule for the first 3-6 months anyway. (Decided after purchasing! )

RedCross WA hires the baby capsules for $60 or 3 months or $120 for 6 months so by the time my baby is in the carseat, she wont need the insert.

HTH