I bet there isn't a single gardener out there who is not guilty of impulsively buying plants in a mad rush of spontaneous enthusiasm... and then letting them sit in their pots for months on end. If you haven't already killed them, get them into the ground immediately. Leaving them cooped up in their pots over the next few months makes them more vulnerable to being frosted, dried up or blown to death by winter weather.
Even if it is not convenient to put them into their final positions in the garden (after all, we all have plans for that grand border, the scented path or the clever pondside planting), shove them into any empty space you can find. It is better to have them alive in the wrong place, than dead in their pots. A spare corner of the vegetable patch (if you have one) is ideal as a halfway house for homeless plants.