Glute Training Tips

Ok so I will start by saying I have been working out (lifting) for Years and I know what exercises are effective for legs and glutes.
However, I have had some issues in the year that has passed since I delivered my son Jan 2012, and my glutes are not where they should be. They are sad and saggy and I have a bit of cellulite on and under. I really need help with them. I squat, I lunge, I step up on a bench with a 30 lb barbell on my shoulder, I do hack squats, incline presses, deadlifts, One legged lunges....but its still not where it should be.
I have a cruise in 3 weeks and really want my glutes to shape up a bit so I look a little better in my bathing suit, but I don't want to overtrain legs. Can someone knowledgeable (preferably a PT or Exercise Physiologist) recommend a good plan for 3 weeks to improve my glutes as far as workouts? Is it reasonable to think I could improve in this short amount of time? I need to leave room to train upper body too and I usually work out on average 4 days per week. 1 hour in weight room, 30-45 mins cardio.
Thanks in advance!