Uncharted 2 save file question

I started a new game and saved it on the same file as my old game, I played about 5 chapters then stopped. When I went back to get some treasures from later chapters, I noticed the only chapters that showed up were from my recent game. I know my old game data isn't erased because i still have all my skins, weapons, treasures and it even says underneath the save file " played 17 hours". I guess my question is do i have to play through the whole game to get those chapters back?

If anyone has a solution or whatnot please let me know, I cant find anything on the net.......

When you saved your new game over, it wiped out the Chapters you already completed. So you have to play through the game again. Thats why if I start a new game, I make a new save file. And it keeps all of the stuff you bought and what you unlocked because you started the new game with all of the treasures and medals right?

Oh well, not really a big deal, the games awesome and now since Im playing on crushing i can go back at any difficulty and use the store. thanks for the replies.