Plant it pronto...it will just flower later.
Or - if you want to wait until the weather warms up a bit - plant it outside and it will flower in Spring....it is amazing how they can catch up....even bulbs that should have been planted weeks ago can still do so and give a good show...albeit a wee bit later but in your neck of the woods - no harm in planting it now! Good luck!

Don't try to keep it until October, though - all that will happen is that it will rot or dry up. It's worth having it in compost and letting it have a go now!