Amazing job, and it's astounding that this is your first quilt. I'm no expert, but I think hand quilting would be difficult with all the seams. A good longarmer could do so much to enhance the work you've already done. I think I would have to find one who specializes in this pictoral type of quilt. I'm sure there are some out there. You could start by contacting the one who did the last supper quilt. I would seriously consider doing a mini project to audition a longarmer before I handed them this quilt.
You may also have to use a non-traditional back: something with more substance than standard quilting cotton. You will also have to be careful about batting. The loft of the batting will definitely be a part of your design. If you decide you want little or no loft you may skip batting altogether or just use a piece of flannel or other fabric (this may help stabilize also).
Be sure to post when you have the quilt completed; I'm sure a bunch of us would be interested to see it.
By the way, welcome to the QB.
Darren