Hi, Ron - It's good news you have some music to post!
It isn't possible to upload music directly to The Listening Room. MP3s need to be posted elsewhere on the internet and then links to the files are what we post.
Many of us use "Box" - at http://www.box.net. The free accounts there have a limit on the size of uploaded files and on the storage space, but for $5 a month you get 10 gigs of storage and there's no limit on the size of individual files.
If you already have web space online, you can simply upload your MP3 to your site's file manager and link to that.
Gary Garritan also provides an MP3 page for people who don't have any other place to store music. Here's the link to the sticky post in The Listening Room which explains about that: