Have you tried The Lil Jack workout? http://www.youtube.com/watch?v=TKCGe2Ezr��And Merry Christmas http://www.youtube.com/watch?v=FdymxP5Kq��
AVOID the stair master!!! If you do it incorrectly it will only make you gain muscle without losing fat and make your butt look bigger!
Squats slim it down and tighten it up.
Squats and the stairmaster