Can't advise on which degree to enrol in because I don't know much about CS. I think @Drdusk knows quite a bit about CS.
However, a WAM of 65 is generally not so hard to achieve. It's a credit average. If you feel this may be too hard for you to achieve (which I don't think you will) then you...
You can achieve a great ATAR with your subjects (not just 60). Since you sit your HSC next year, use year 11 to determine which subjects you will keep for next year.