Coralbelle, so sorry to hear of your loss!* If the peony is potted you can plant it now.* They tend to live a very long time, so add lots of compost to the planting bed and mix it in.* Do make sure the top of the 'eyes' aren't planted deeper then 2".* I know that sounds shallow, but they will rot if planted too deep.*
I don't remember which link you are referring to.* Maybe it was this one about planting?
Btw, I'm a bit concerned that the peony was just dug up now.* It's best to do this in the fall.* I realize you had no choice, but do watch it carefully and don't overwater it.* It could take up to 5 years before you see flowers, so don't get discouraged.*
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.