question about vocal treatment

I have a low quality setup at the minute and don’t use an audio interface. I use a blue snowball ice USB condenser microphone and it tends to pick up some hiss… other than getting better mic or improving setup, what can I do to erase the hiss?

I have tried treating the higher frequencies but it tends to take away from the vocals (female) any plugins, tricks or tips? (Using Mac OS / GarageBand)