Help: Got one ticket for passing school bus

在两个lane的马路上， 我和校车是面对面开。 我开过时， 校车只是SLOW DOWN， 还未有take out the STOP sign， 我车子未停， 就开过去了。 Police issued me a ticket for passing school bus unloading, saying the STOP sign was out at the same time when i was passing it.

现在 ticket上有$75BOND， 还要上庭。 请问：

1) 我该如何向法官解释? When the school bus STOP sign was out, I have already passed it.

2) 还有这种情况会有何种处罚？ 我在网上看到好像是$500， 3 month suspension, 5 points in IL.

I am in Illinois.

先谢各位好心建议！