Need help level up my Char PS3

I was forced to change my ps3 borderlands 2 disc in order to play DLC ( disg region is different from my psn acc region). I Think i need to start all over again because i can not play the previous save ( lvl 50 char).

I really hope someone can help me level up my char to level 50 or 61, so looking forward for kind response.

PSN ID : Tournesol881210
Thank You So much