The problem lies probably in the fact that you didn't find out how to tweak the default settings of your version PDFCreator.
Bear in mind that your conversion path is a 2-stage process, going
.doc =>> .ps ==> .pdf
The first step is done by a PostScript driver, the second one is done by Ghostscript. PDFCreator is just a frontend to this process. The conversion uses a .ppd
(PostScript Printer Description) file file, which may or may not contain lots of bells and whistles to tweak output resolution of images.
You are free to exchange that PPD file. I do not know which one PDFCreator uses by default, and which default settings are enabled in that PPD. You also didn't tell which version of PDFCreator you used. BTW, the latest version of Ghostscript nowadays is v9.02 ...