This didn't quite work ended up using Clonezilla (free linux clone distro) worked like a charm.
So for those wanting to take they're existing USB with EXT partition and move it to a newer bigger drive here's what worked for me.
I use a Mac, so I used VMWARE Fusion as my main tool.
1) Download Clonezilla, use VMware Fusion to boot a VM with the Clonezilla ISO and clone the USB drive to the new bigger one.
2) Download Gparted, boot it in a new VM machine with VMware and Resize the partition to occupy the complete drive.
3) You're done
