I found lineart versions of a lot of military insignias on sights like this one:
http://www.349amw.afrc.af.mil/art/mediagallery.asp?page=2
Wikipedia (or Wikimedia in this case) also often has .SVG files which are vector based web pages that many vector programs can open (I can't speak to Corel, as I don't have it...) but I was able to open the SVG file in Adobe Illustrator and save it as an EPS file, which is a very standard vector (line-art - not pixel base, so it can be scaled up and down without loosing quality). I would be very surprised if Corel did not offer to open EPS files, so in the least this may save you a bit of time Constance...
The Wiki file was labeled and E-5, and I'm not sure what the difference is, but they look pretty identical to me (short of a color difference...)
I've posted both files here if you want/need them:
www.toddlajoie.com/publicfiles/IAP/