Nice quilt! Love the scrappy feel and the opposites :)
Are these fabrics that are in your top? I'm not sure I'm seeing that green in there.
What about putting a band of the green up one side and top, the red on the other side and bottom ... a little like an 'attic window' border. I'd use the more solid colours so they 'frame' the top. The pattern might blend in too much?
I'd make the bands the same width as the strips you've used in your blocks (so the band would finish 1/4 as wide as the block).