High school production of Mid summer

[laaaakes5]

i am a 17 year old at westview highschool in san diego cali. i have been choosen as sound designer for the show. the director wants to record some original background music for a song that a student is to sing in the play. luckly this individual is in my band so i have an advantage there. he wants to record the piano siting in his room. its pretty nice i have no idea what kind. however the music room has a very expensive synth. with a billion buttons, i think i heard that it cost like 3 grand or something i do'nt kno. but he wants piano parts in the song and then some string of horns kinda in the back ground. the song is supposed to be a layabye. i was wondering wiether i should try to mic the grand piano or to use the meyboard thing the band has, thru a cable wiether midi or audio, or to use stuff like reason and things i've got to try to get a sound. kinda a really browd question i kno. but i do'nt kno what to do really. i will take pics of all the stuff, and the areas to c if the accoustics or the room are good. any help would save me. cuz the music i record is goining into the show, so i'd like it sound as good as possible. and if it goes well itd be a nice show off thing too. so thank for anyhelp.