Give me strength!

[Theseus]

Defined well by the Cambridge English Dictionary with an example in context:-
something that you say when you find someone else's stupid behaviour or inability to do something annoying:
“Oh, give me strength! Do you want me to do it for you?”
What, please, is the Greek equivalent of this common English expression?

 

[cougr]

In the context of the example sentence you provide, one might say: ο Θεός να μου δώσει υπομονή/κουράγιο (or some variation of this).

 

[cougr]

Another expression of exasperation or frustration that comes to mind and may work here is έλεος!