If your past two weeks into flowering it isn't going to grow much more - I mean, in the first two weeks is when it stretches a lot, then turns to consentrate on flower growth. If anything, I'd say you'd lose yield if you attempted to transplant now!
BUT...
If you still want to try it, you can minimize stress by cutting a hole in the bottom of your current pot (I'm assuming it's plastic), and simply place it in another bigger pot with the roots of the plant in contact with the soil in the bigger pot (with the medium of your choice). It's not ideal, but I've done it before.