Sorry, my bad. I somehow spaced and saw MIA instead of MCO.

It seems like this is all one ticket. There are still a ton of connections on AA and US from Orlando to LA so I do think taking a deep breath is in order unless the OP HAS to be in LA early. This was a valid ticket so it is the issuer's responsibility to fix it. Maybe asking whoever ticketed it originally to switch the Sao Paulo flight to MIA instead of MCO. In any case, it seems like a case of systems not talking to each other. TAM shows the AA flight at the old time and therefore can't/won't change the ticket. But I certainly think they will do the right thing eventually and it is NOT the OP's responsibility to buy a new ticket from MCO to LAX.