If you want to get the color correct there are several steps to take:
1. Use a monitor which is capable of good color calibration. On most LCD monitors you have to turn the background brightness down to get good balance.
2. Use a color calibration devicw like the DataColor Spyder or the ColorMunki and follow the instructions in the software.
3. Use software like Photoshop which is cabable of using color calibration.
4. Get the ICC profile for the printers at Costco (available online) and use it to 'soft proof' you pictures when you are editing. That way you can adjust your file to produce the color you want on the final print.
5. Tell the person processing your prints to disable their color correction when printing your job.

Check the web for some very good tutorials on color calibration and printing. Good color balance is an art.

Maury