Dust is a fact of life!


I see that you're shooting at f/25, use larger aperture, like f/8 and larger and the dust should be less visible or maybe disappear all together.


You can do 4 things to get rid of the dust spots
  1. Use a rocket blower, but stubborn dust particles are hard to be blown off.
  2. Clone them out in post processing
  3. Wet cleaning, just goolge "Sensor Cleaning"
  4. Send it to Canon, it's free if your camera is under warranty, $30 if not.