You do not need Linux or Linux expert to copy image to you windows computer from Kobo internal SD card plugged into windows computer using Flash Drive Image Creator. Then copy this image to new same size or larger SD card. Easy to download the 2 programs below and use them. To make it fool proof and ease you mind set write protect on SD card while copying image to you computer.
If the image you copied from a smaller SD card and writing to a larger SD card the image is still same size as it was on the smaller SD card. I used Parted Magic to expand out the last partition of the image on the new larger SD card to use all of the unallocated area of the new larger SD card.
Parted Magic is ISO image you write to CD or DVD and have your computer boot up from this disc to run the utilities on the disc. It boots up to a live linux operating system that only runs in you computer's ram until you turn off you computer. The other option is to down load and use a "windows partition tool" for you computer. This is easy to find with web search.
Parted Magic and other disc utilities have nice graphic image showing what you are trying to do then you tell it to make the changes. If you don't like the results try again. No harm done. Worst case you reinstall original internal card. Save the original card so you have a backup image and don't have to ask for one from someone on this forum.
Flash drive image creator
http://www.vconsole.com/client/?page=page&id=28
Flash drive image writer
http://www.vconsole.com/client/?page=page&id=29
PartedMagic
http://partedmagic.com/