well ive never used goldwave before, but it should be partly the same as sound forge 7.. when you have you mp3 converted to a .wav ( you will want to delete the converted .wav file after youre done cuz its about 30mb just so you know.) then select the wave on the clipboard or new project in your program.. then just simply save it as a smaller .wav file ( not compressed, will not play right ) make sure that its 8bit mono and then save it. the file should be just about 567k's big then you can either just put it in ambient_generic or go back in the sound program select the newly finished smaller .wav file and put cue, or repeat point after the end of the song. thats all there is to it. ( oh ya! and save the file into the valve/sound folder.
hope it helps your prob and my writers cramp.