How much bigger do you want the quilt to be? It looks like your block size is 12" so if you add another row then the quilt will your top will be 12" bigger. It also looks like you are showing 3-2" strips wich when added together will make quilt 12" bigger. Do you have enough fabric and the energy to make more blocks? if not then add the 3 colors for the borders. I think they compliment the blocks nicely. I think either without or with borders would look nice. I think that the binding also will frame the quilt which would look good in the purple.