You've got 17g left. So this is enough to raise 17/25 times 500g flour = 380g.
But the yeast/ flour ratio is not an exact science. You need enough yeast to raise the amount of dough, but a little less will work but might take longer to rise, and a bit extra will basically go to waste - you'll still get your 500g pizza dough. So your question is better phrased as "how much more dough can I make" rather than "how much more flour do I need"