Buy a bigger CD.
Sorry quick and easy humour.
If you use another program to recompress the file then you will certainly get a worse looking file.
You could try cutting the credits off of the end, that would probably save some space. Something like VirtualDub would do that for you.
WinZip 9 has a new "Super Compress" mode. Other choices are WinRar and WinAce.
Other than those I am not sure what else you could try.