D.D.
You have to totally change your parenting tactics. Make your children your allies. LOVE them, Cherish them. Yea, I know it's hard. Reward them when they do something good. Constantly be on the lookout for good behaviour then compliment or reward. Overlook the bad as much as possible.
I'm constantly doing this with my daughters. I tell them that they are made in the image of God and certain behaviours are not appropriate. When they swear, they get their mouth washed out with soap. If they misbehave, the park has been cancelled. I use events such as Chuck E Cheese and Science Center as rewards for behaving well all week. I started with typing a list of rules that they are to follow. This helps all of us remain consistant. Then, I did a sticker chart that you can stick a sticker in every 1/2 day they behave (your can make it every hour if you want) - get LOTS of stickers. All of a sudden the behaviour turned around. I have VERY bad parenting examples myself, so I used The Nanny and other people's ideas for what to do. Most of all, LOVE your kids. Make sure you are spending active time with them. If not, it doesn't matter what you do, they will misbehave for attention. So, give them attention for positive behaviour. Often my kids misbehave if I'm overworked and haven't spent enough time with them. In fact that is the #1 reason they misbehave, in my opinion.
God bless you and I hope that in no time you will be enjoying your children.