I wish to change my system to use UEFI from the older bios system

but I have run into the single problem of changing the disk from MBR to GPT

I have lots of things I need to back up and i want my windows system to be how it is now. The problem is Windows system image apparently does not like applying MBR imaged disks to GPT disks.

So i want to know how i can change my disk from MBR to GPT and get it working with the UEFI without losing anything before i get my new motherboard.