well..the song doesn't seem that high so i don't know if that is ur worry or not (since u say u have a high voice)..but the whole song is basically in natural voice. You don't have to sing every part the exact way that he sings it. There have been many times when i couldn't sing a part of a song the way it was sung so i had to change the notes up a bit..there is nuthing wrong with dat; add your own style and make sure u do whatever u feel comfortable doing. If you want to learn how to hold the note my only suggestion is for you to break the song into sections and practice each part individually until you make it thru the whole song. It's not that hard to sing: i believe that if u can tlk u can sing
. It doesn't really sound like a difficult song..so i'm sure that u can do it..the most important part is to make sure that you sing from ur diaphragm and
breath...let me know how it goes