Native Koreans correct me if I am wrong pls.
-기 위해(서) means "in order too" or "for"...:
For me to go traveling (in order to go traveling) I need to save money
여행을 가기 위해서 (저는) 돈을 모아야 해요.
Then there is -에게 or -한테, which would mean "for" when you give a letter or gift:
I bought a present for Nyancat
Nyancat 씨에게 선물을 샀어요
Nyancat 씨한테 선물을 샀어요
Finally, the word "you" is a bit funny in Korean language. For wife or husband and close friends you can use 당신, but in most other cases you would use Name + 씨 or name plus title or something. 그대 is more used in literature and songs.
Good luck!