Halftones on photoshop cs3 extended

If you want to get two colors out of one screen ,when flat screen or rotary printing, the solid area would be 100% solid and its halftone area would have a raster in it. In photoshop, it would be different greyscale percentages in spot color channels.

Export Corel Draw in CMYK Jpeg 300dpi, open in Photoshop and print in colors separation

Get a postscript printer installed, printing to file, laserwriter/adobePS and you can print directly to separations, Corel or Illustrator will let you define your halftones.
You don't say what printer you are using, an inkjet will print millions of tiny dots that a screen can't hold, a halftone groups those dots into bigger dots that can be held on a screen.