Here is how I would approach it:
I would cut the blocks off and cut them down to individual blocks.
Sew a simple border around the panel.
Then find a block pattern (or multiples) that play nicely with those blocks and in the same size.
Sew enough blocks so you can alternate all blocks as the next border.
Sew another simple border.
If it's big enough at that point, finish.
If it's not big enough, add another row of blocks and another border until it is big enough.