Sounds as if you are spending far too much time talking to them and not enough enforcing the rules of the house. They are old enough to know right from wrong and with hubby away you are trying to play both roles as well as friend. The only role you should play is parent.
With dad away it's too easy for him to fall into the trap of I've been away from my family and only want to play and have good times. Dad needs to get on board with the punishment factor as well - if they have misbehaved, no treats, no rewards, no family outings. It's okay for you and hubby to go out - get a sitter for them.
They already have your number - do something wrong and mom talks to us. We agree with what she says and then we'll go find something else to do. They are a force of 2 against 1. Next time they do something they are old enough to know not to do - punish them. Send them to seperate corners to sit in for 15 minutes. If they spend all day sitting in the corner - so be it.
Ground them from something they like, want to do, a place they like to go, social outings with friends. Reward them for good behavior, plan things to do then is the behavior is bad take the plans away.
We have a busy schedule at our house with play dates, trips to see friends and family, going to the movies, the park, etc. I put those dates on the calendar for everyone to see and we talk about our upcoming plans. When our daughter gets out of line, disobeys, etc, we start removing things from her schedule. It does work. No kid wants to be only one not attending a bday party, or a sleepover, or not be able to say they say XXX movie.
Good luck with this one. If you don't get it under control now you'll be the mom with "those kids" that we've all been around.