Slightly longer answer means that with the blue skin (the default one) you'd have to go editing Skin files.
To make it the shortest exercise possibile you could probably edit the c:\program files\devnz\gbpvr\skins2\blue\baseskin.xml file and where it has font entries add 1 or 2 points to each font definition.
For something a bit more user friendly the Community Skin as a GUI plugin that allows you to see the changes.