I'm glad to talk to you.
would be translated as
너와 이야기하게 돼서 기뻐.
Your attempt "너한테 이야기해서 기뻐" is grammatically correct. But it sounds unnatural.
But, the grammatical correctness is not the whole element of good sentence.
You need to consider native Korean way of thinking
1)
이야기하다 is not a one-sided action but a mutual action.
So, 이야기하다 always used as "와/과(with)"
to talk to A => A 와/과 이야기하다
2)
이야기하다 is not a moment action but a long duration action.
The feeling 기쁘다/반갑다 usually applies to a moment or situation.
So, 기쁘다/반갑다 is often used with "게 되서(glad of the situation of doing something)"