You can install additional fonts without building your own Win CE image.
The easiest way is to use the AutoCopy function. Just copy the font file in \FlashDisk\Autocopy\Windows\Fonts.
Now, on every boot the fonts file will be copied automatically in the \Windows\Fonts folder and are available in Win CE.
Load font dynamically
To load the font dynamically you can use the Win CE API: AddFontResource
For more information about this function see the Win CE help.