1) find some webspace.
2) upload the track (the webspace provider should tell you how to do this as it can very from 1 site to another).
3) post the http link to the track on here using the [url] tags.

if your quick (as in the next few mins of me posting this) i'll host the track for you, but u'll have to be quick as when i'm offline i wont be around again till 2 weeks