Try opening your .eps files in Acrobat, save as a PDF. In Acrobat, go to File> Properties> Fonts to see if the fonts are actually embedded. If they are, your PDF should print as it looks on screen, If they're not, you should ask them to send you a new file, (a PDF with embedded fonts). You can also place this PDF into another program, InDesign for example. You can make minor text edits in Acrobat, as long as the letter/font you need is already used at least once in the PDF (embedded subset). You could use a plug-in like Pitstop to do more extensive editing but it's expensive.
Edit: Preview does not support all PDF functionality, like overprinting and transparency, use with caution.