Well done for loosing 3kg.
Sounds like you are doing very well during the week. I found on the weekend the most important thing was to be really busy so I am distracted by the activity rather than food.
I give myself one treat on the weekend a weight watchers diet desert.
That stops me from eating junk food. I up my exercise on the weekend as there is more time available. I also chew sugar free gum when I get the urge to snack. I prepare my food early ahead of time so that I eat well.
I am attempting to increae my sporting activities on the weekend which is easy as I used to do none at all. I now go bowling instead of the movies and take a healthy snack with me.
My husband and I walk to and from the bowling alley about an hours walk.
I use a sticker chart to track my daily exercise and the number of times I exercise. Someone on this site suggested it and its a great visual idea. I can see at a glance how many times I exercise within a day or a week. Very motivational.
The other thing I do on the weekends is try and mix up my routine for interest sake. Say one walk, aerobic exercises , then a muscle toning workout. I'm not very good at the exercises but I am continually improving.
Hope this helps.