1) Unless you have a monitor which you can adjust for RGB (Red/Green/Blue) then not all the colours will match exactly. The most important adjustments are brightness and contrast. The idea is to match the calibration print to the screen image as closely as possible. This will mean that in future how your images appear on screen will be how they are printed by FrogPrints.
2) If you don't have a copy of the calibration image, but already have prints from FrogPrints, you can also use these to calibrate your monitor. Bring up one of the images on you monitor and hold up the photo beside it. Adjust the brightness and contrast to make the two images match as closely as possible. Do this with a couple of photographs, to make sure you cover a range of colours.
3) If you have Photoshop, you can use Adobe Gamma which is a utility provided with Photoshop to help calibrate your monitor.