I'd be happy to try and help, but I don't understand quiet what you mean. Do you want the quilt to remain 51 1/2 by 61 1/2, but have more rows? Or do you just want to add more rows making it a larger quilt?
If you want to just make it larger, just make the blocks the same size as the ones you are making, just count how many more you need to make to get it the size you want.