This micro-tool lets you convert a GameMaker font for use with my Pixel Font Converter!

GameMaker has a number of options for generating font texture pages, making it a good choice for generating the initial font texture before fixing it up by hand.

Font YY:
Font texture:

Extend left:

Extend right:

Extend up:

Extend down:
Glyphs:
Right-click and Copy\Save As the image; Copy the glyphs.