Step 2
Make sure that the circle with the radial gradient is still selected and go to Object > Expand. Check the Gradient Mesh box then click OK.
Focus on the Layers panel (Window > Layers), select the newly created group,Ungroup it (Shift-Control-G) then hit Alt-Control-7 (or go to Object > Clipping Mask > Release) to release the existing clipping mask. Return to the Layers panel and simply delete the top 290px circle (the former clipping path).