How do I transfer my Grand Theft Auto IV saved date from one PS3 to another?

I had an old ps3 with all of my grand theft auto saved data. I have almost beaten the game and when I try putting it on a flash drive and transferring it it just says, "you did not create this game data, file can not be loaded." So how can i transfer my gta game data with out transferring everything on my ps3 wth a back up.How do I transfer my Grand Theft Auto IV saved date from one PS3 to another?
If you want to have full "control" on the game after you change the PS3 you should change the HDD, which is kinda easy(check it on YouTube, you just need a screwdriver).Or, go to Game Saves press triangle and copy. Then, copy everything you can on a flash disc. For trophies(I think it had right?) just sign in to your PSN account and they should sync. After this, when you sign in on another PS3 with your PSN account your trophies will be shown.



Hope it helps!