I would imagine because it's an evergreen you should be able to prune hard in spring, after the frosts have passed - this should allow time for the new growth to harden before next winter. You will be cutting off this years flowers but I'd imagine from the sounds of it that that is the least of your worries. You may already know this but prune to a new axil, branch or bud where you can and keep a good frame work and shape, encouraging the next shoots to go where you will be happy with them. On a side note have a think about the plant itself, whether you actually like it or not and could there be anything else you could change it for - maybe something a little lighter on its feet.