If your file is over 128MB in size, you should contact FuzzY-LogiC who is our audio mod and he can import any mp3 into the audio archive for you under your name.
You'll need to upload it either to his FTP (more ideal and quicker, he'll give you details) or else to a file-sharing website where we can download it and then import it for you.
Any probs give me a shout. I might make this clearer on the upload page shortly...