Why don't you do it without using additional softwares...?? In photoshop, you can mark guides at specific places, (for eg, if you want to print in A4, keep vertical guides at 8.27" position, 16.54" position etc and horizontal guides at 11.69, 23.38, etc.. 'coz A4 measures 8.27 x 11.69) and crop to that position, and save as separate picture.
One word of advice: If you are gonna make multiple prints and then paste all together, allow for overlap between the images, so that you can paste one over another.. Hope I made my point clearly..!!