THT your guessing is correct, the answer Cyaoeu`s is correct too and nice translation. you got perfect solution and there no explain for this answer, so i will give you phrase insted. あなたがいるから、がんばれる。: i can do this because of you. "あなたがいるから" あなた giving it energy, whatever the willing to her career, things make want she do to him/her, giving her life meaningful, etc,. another example when it is simple object. 通れません、・・・・ あなたがいるから。 i think you understand this あなた no problem :D

I would translate it as "because you're there", as in "you're there for me".

anata ga iru means ,your there by my side