build 1 scout per turn until you save up a few turns of resources. this should stop your planet from being attacked.
Remember to set the scout on Planetary Defence, otherwise it'll sit there and let the fleet take the planet.
then make a massive fleet and win. or use this time to make planetary defence - instant win.
Instant, but ridiculously expensive, win. I struggle to build much of a fleet because of my Planetary Defence since it takes 30% of my income.
