Another way to check thermometers is to put a bunch of ice in some water and then stick it in there after a few minutes. It should be right around 32*.
I'd say don't concede and toss it just yet. There are ways you can attempt to fix this. I've read that this French Saison yeast is good for stuck fermentations because it has a crazy high attenuation. A starter of that at high krausen might be worth a shot.
There is also Amylase Enzyme (Beano) that I've heard can break down the complex sugars into more fermentatble ones.
Word of warning: I have never had to try either of these methods but from lurking on forums for a while I've read of each of these being successful in the past. I think your right in the fact that you should not add your dry hops if its really really stuck. No need to waste them but it's worth a shot to get it going.