Need help with text size not fitting on the screen.

[Angel of Pi]

I am trying to change the server chat text size by changing the font size in the advanced settings...
http://imgur.com/ggceBwh

But the text in the menu ITSELF isn't even on the screen so I can't change it!! ;_;

My resolution is 534x320 if that helps...

I just need help. I REALLY want to adventure in multiplayer but the server chat takes up half the screen.

*cries a little*