Calibri font doesn't work in postscript device, only in .PNG

[Lukas-1]

The png device works fine. The postscript device either gives me irregularly spaced letters, or an error like the following:

Error in mtext(unit_text, at = par("usr")[1] - (par("usr")[2] - par("usr")[1])/30, : metric information not available for this device

Calibri is a screen-optimized font that comes preinstalled with all new versions of Windows / Microsoft Office as the default font for Powerpoint and Word, and so it's a safe choice for use in Powerpoint files that may be transferred across computers. I would like my R vector graphics to have the same font as the powerpoint text.

Has anyone gotten Calibri to work on their system? Might there be a fix for this problem? Thank you for your help.

sessionInfo()

R version 3.1.1 (2014-07-10) Platform: x86_64-w64-mingw32/x64 (64-bit)

attached base packages: [1] stats graphics grDevices utils datasets methods base

other attached packages: [1] Rttf2pt1_1.3.1 extrafont_0.16 RColorBrewer_1.0-5

loaded via a namespace (and not attached): [1] extrafontdb_1.0 tools_3.1.1