She is not able to take your call at the moment.

她现在没办法接你的电话。

I'll have her call you as soon as she comes back.

等她一回来， 我就请她马上回电。

I'll think about it and call you back soon, OK?

我考虑一下，回头我尽快打电话给你，好吗？

That's fine. I think I can wait till then.

好的，我想我可以等到那时候。

Great and please make sure the room has a nice view of the park.

很好，要定那个可以看到公园美丽景色的房间。

I'm calling for your assistance.

我打电话是要您帮助我。