Maybe you could just get two Cosco Sceneras for now. They are pretty tall and harness to 40 pounds. There is nothing fancy about them but they are only about $40.00 at Wal Mart and they are very safe seats. For $80.00, it could buy you a little more time to wait for the 50 pound version SafeSeat 2. Just a thought since both kids will fit in them for awhile.