Parsley develops a long tap root and mature plants don't take kindly to transplanting. It tends to make them bolt early. Parsley is a biennial (although some plants will carry on a bit longer) so yours will flower anyway next spring and you will need to start new plants for next year. You don't say where you are in Canada but if in a milder zone it might be better to protect the parsley outside where it is with a cloche or fleece. If you really have to bring it in I would dig up a huge clod of soil with it and put it into the biggest pot you can manage. In other words transplant it without it realising.

There is no trick for keeping herbs going other than knowing their individual characteristics and acting accordingly. Cilantro is an annual and is short lived naturally, as is dill. Both need sowing several times in a season even out in the open. Neither would live indoors for long however careful you were.

Parsley will tolerate quite cold weather, and in my climate I have harvested it well into November. Last year I brought it into my unheated porch and was able to enjoy it for many months thereafter.

However, it eventually became infested with aphids, as often happens when you try to bring plants indoors, but by that point I felt they had produced above and beyond what I had expected anyway.

So if your area is not too cold, you should be able to overwinter them outside for quite awhile.

I would plant new ones for inside. If you plant them now - they may be ready just when the outside ones give up under the snow.

Cilantro likes it cool - perhaps it was too hot inside for it? also - not sure if that one like transplanting or not.

No, cilantro does not like transplanting. It is a short lived annual and disturbance encourages bolting even sooner then normal.