Welcome to the board.
First of all congratulations on the weightloss
In my opinion weightwatchers is over-hyped bull-shit. You pay money for this when you can change your diet around yourself.
Anyway that is a different matter.
I really think you should stop with the ski trainer, your better off upping your running to 20mins ....after a while once you get more used to it go build up gradually to 30mins over the weeks.
Once you are used to running at your own level for 30mins just up the pace little by little every time.
The higher intensity you run at the more fat you will lose - but if your diet sucks it is that much harder.
Losing weight is mainly about sorting your diet out.
If you post your diet here i could help make minor changes for the moment and then eventually you can reform your diet.
By the way you say 'thinking of doing rowing to help get rid of my stomach' - It doesn't work this way.
Most people think that "if i do crunches it will directly get rid of the fat on my stomach".
This is a totally wrong perception.
By losing fat your total body composition will change not just one area.
Add the rowing machine, won't do you any harm.