Once, these words have a little bit different nuance. Actually '흥분하다' is stronger expression than '설레다' '설레다' is feeling excited before something you expect and look forward to happen. And 설레다 implies 'flutter' as well. 흥분하다 is also sometimes used as feeling excited before something you expect happened. But mostly 흥분하다 is feeling excited while or after you experience something, or feeling excited about something already happened. :) So actually you can use both 설레요 and 흥분해요( or 흥분돼요) for your sentence. if 'I am excited for your return' means 'I am excited cause you come back soon.', then "네가 돌아와서 나는 설레어." or "네가 돌아와서 나는 흥분돼." are possible expression ^_^

Yes yes i know ^^ They more likely like to use sentences close to "I'm looking forward to it" "I anticipate" but i didn't really know about your examples, thank you so much ^^

I'm not Korean but you could also say 기대되다, just thought I'd add that since it's probably most commonly used from what I experienced, in fact I barely ever heard 흥분하다, 설레다 occasionally. Another possible expression could be 빨리 [나왔]으면 좋겠다. Which is more like... "I hope this happens soon"