我再帮您和老板争取一下，英语怎么说？

I'll talk with boss and try to give you more discount.

I'll talk to the boss for you once more.
I'll negotiate it with the boss for you one more time.
I'll talk to the boss to help you once more.
I'll discuss it with the boss to fight for you one more time.
I'll discuss it with the boss to bargain for you one more time.

I would like to help you and to fight for the boss

I would like to help you and to fight for the boss

I would like to apply to boss for you~~

I'll help you get more chance from boss.
关键是争取的是什么，英语中一定要说明具体的东西才好翻译