Can't get a color logo to print in color

PostScript newbie here... I have two issues with a postscript image I'm trying to print.

I have a green logo .eps file that I print to an HP color laserjet printer via a Linux server, but the logo only prints in greyscale.  I have reviewed the image code, and tweaked the code to specify color (e.g. changed the "image" command to "colorimage"), to no avail.  Can anyone assist me in getting a color printout?  Here's the main part of the code (specific image bits removed):

%!PS-Adobe-3.0 EPSF-3.0
%%TemplateBox:0 0 188 78
%%BoundingBox: 0 0 235 97
%%PageOrigin:0 0
/width 188 def
/height 78 def
/pixwidth 235 def
/pixheight 97 def
/picstr width string def
/dopic {
gsave
width height 8
[width 0 0 height neg 0 height]
{currentfile picstr readhexstring pop}
image
grestore
} def
pixwidth pixheight scale
dopic

.

.

(image bits here)

.

.

%%Trailer
showpage

The second issue is that I can't get the image to embed in another page - that is, when I call the image to print in a C program, the printer spits out the logo on a separate page.  The goal here is to embed a color logo (the .eps file) into a certificate, where the rest of the certificate contents are generated by PCL commands.  I've been able to embed a PCL image (too much aliasing) and an HPGL image (plotter print dulls sharp corners), but the .eps file doesn't want to play on the same page as the certificate.  Any ideas?

Any help is appreciated!

- Bry