For this type of job you will need to use an advanced image editor because it involves copy and paste of multiple layers and images. I would recommend you Adobe Photoshop but since it's a paid software (trial version with full features is still available) a different approach is always welcome, which in this case would be GIMP.
GIMP allows you to work with multiple layers which is exactly what you need. Simply create a document with sizes you want, and then open the label document you have and use the rectangular select tool and manually crop one single label. Then calculate how many labels you want based on the resolution of the document you previously choose and resize the label how many times it's needed for it to fit on the page. Then paste the modified label until you achieve what you want and that's it.
