are the leaves really as dark a green as they look in the pic? if so, then it's (most probably) 'autumn joy'. especially if it's flowers turn out to be pink.
i've got one that's similar to yours - the leaves are a light green and the flower is a lavendar...
Wow, Rosepetal, that is really going to be beautiful! It has such a bushy, compact shape! I hope you're going to post a picture of it when it blooms. I would love to see it, especially if it's pink!