Hi janieee, first, I am very very sorry for assuming that you'd play that for HSC >.<" so sorry, I just assumed because you were looking for pieces and you found Bumble-bee and I thought that would be one of your HSC... so sorry >.<". But yeh, if you play that for like school music festival, that will be AWESOME!! Im sure you'll manage it!! It'll be great!!
ur_inner_child 100% correct. Marimba usually range 4 - 4.5 octaves (depending on the maker... Yamaha comes down to a low F... 2 F's below middle C... that's 5 octaves... sounds PHAT!!) but there 5 octaves. Marimba are made out of rose-wood. Gives it a very very warm mellow tone. Xylophone as ur_inner_child said, is brighter. In the old days, xylophone are made out of bones... very clanky and bright. Nowadays, xylophones are made from material called kelon. (man I feel like a historian now >.<" hahaha). They make an even brighter sound BUT!! they have longer sustain... still short but not as short as rose-wood xylophones. Mallet/Keyboard Percussion instruments produces better sound when they are made out of wood. Oh and Premier xylophones (English made) they do 7 octaves... I'd love to have a go at one of those!!
But yeh, usually xylophones are 3 - 3.5 octaves at the most 4.
Pieces for marimba/xylophone. There are lots and basically you can turn anything into an arrangment/transcription to a marimba/xylo/vibes piece. One I am doing for Semester 1 is a piece called Ulpirra by Ross Edwards. This is written for solo treble woodwind, it's awesome!!. (I suggest you to play the piece... if you decide to play that... an octave lower, just gives it more of a humour and joyful feel to the piece - the intention of the piece). There are tonnes of Bach repertoire out there but be warned, most and near all require 4 mallets. Work on it and I'm sure you'd be able to do it! Mind over matter! Bach Inventions? Bach Partitas for Solo Violin? Shostakovitch The Golden Age Op. 22a: Polka? Um... there is also a piece by Ross Edwards that is written for marimba and I think (if I'm not mistaken) some aux. percussion, called Marimba Dances. Ross Edwards Prelude and Dragonfly Dances? So there are plenty out there and basically, if you hear something you like, look at the score and see if you can transcribe it! I am already planning to transcribe Schoenberg
Sechs kleine Klavierstücke Op. 19 for Vibraphone. Oh and keep in mind, (i don't know I think ur_inner_child can back me up on this cause she's a composer) when you transcribe music, make sure it fits musically? No point transcribing like... I donno for example, Brahms Symphony No. 4 Movt. 1, cause it's very runny and very thick and lots of strings - you wouldn't achieve the same musical feel to it. So think about that as well. Schoenberg Sechs kleine Klavierstücke Op. 19 works well with Vibes because it's very atmospheric and that kinda stuff. Get a recording of it and you'll see what I mean.
I think that's a bit too long of a response >.<" should stop there anyhow, tell me if you do need more pieces and I'll try to suggest more to you ok?!! All the best!! Have fun!!