Eating right and exercising is a good start but also toning exercises are very important. I have the same problem with my back.  I found that when I did pilates, it helped a lot. They have specific exercises that target those areas, I ordered a dvd from ebay for the back. It helped a lot and toned the area a lot faster and each dvd is only 20 minutes, you should definitly see a difference on one month ( you will probably see a difference in 2 weeks if you do it religiously every other day.

Here are some exercises to do if you have a pilates ball.