How to get animated gif small enough for google ads

Hi I'm new to animate. I created what i think is a simple animation, and even with going down to 32 colors when exporting the gif, it's 301k, and it looks pretty grainy.

How can I get it small enough, I think it has to be 150k, and still have decent quality?  or am i using the wrong program for an animated gif, and animate is better for html5?

Thanks!!