Why don't you try doing something at home during the week and hit the gym on the weekend? Twice a week is not really enough to get some good results. You could always try to get some workout dvds and do them at home. I have been using them for about 20 years and swear by them! I used to be a gym goer, but I found that I didn't always like the instructors or the types of classes that were available when I was able to go. Also, I found the cardio equipment quite boring! The great thing about workout dvds is that you try a few until you find a style or instructor that you really like and then just buy their whole range. I sell the ones I don't like so much on ebay so it doesn't end up being a waste of money.
If you get a good selection of both cardio and strength training dvds and even throw some pilates or yoga in the mix, then you should be well on your way to getting those 10kgs off.