Looks like it's time for a new machine,
MarionsQuilts! 
On a more serious note ... look for QAYG (Quilt As You Go) explanations.
I know
MaryKatherine (another Ontario Quilter!!) gave a very detailed explanation
about enlarging a quilt some time ago. I'll take a look and see if I can find the thread.
Or just PM her?
Found it !!
Enlarging a finished, washed and shrunk OBW quilt.
Because we quilters always like to know the whole story about a quilt ....
Here's the two earlier threads while she was making the same quilt.
(found them before I found the one I wanted for you!)
Work in progress OBW and My Space
My quilt is TOO SMALL