Where we found the Seals, and their current state (broken or not):

1. Mat found the first in the Eye of the World with the Horn of Valere and Dragon Banner; it was already broken.
2. Bayle had one, intact, which he'd bought from a Saldaean antiques salesman. It was taken by Turak; Moiraine found it after the fight at Falme, and it was broken by then.
3. Turak had one in his cuendillar collection. Moiraine found it along with (2). Also broken.
4. Moiraine found one in the Stone of Tear's Great Holding, intact.
5. She found another one in Rhuidean, and made a scratch.
6. Nynaeve found one in the Panarch's Museum in Tanchico; it was accidentally broken on the way to Salidar.
7. Mazrim Taim gave the last one to Rand, saying it was found in a farmhouse in Saldaea. It is still intact.

So three seals are still intact (4, 5, and 7), although they are very, very weak. The intact ones are all in Rand's possession (or the possession of people on Rand's side). Also worth noting is that Rand is not aware of the seal Nynaeve found, or that it is broken already [COT: 24, A Strengthening Storm, 558-559].

In the Prologue of COT, Davram Bashere's wife Deira and Lord Dobraine are attacked, separately, in two apparent robbery attempts. We are not told what exactly the would-be thieves were looking for, but on discovering Dobraine, Loial blurts out, "'This is very bad! If there were more than two, Karldin, if they found - !'" [COT: Prologue, Glimmers of the Pattern, 93]. It's been speculated that Bashere and Dobraine were targeted in the belief or hope that they were guarding the seals still in Rand's possession.

Why now is not known, nor why Taim (almost certainly a Darkfriend) gave one to Rand in LOC if the Shadow was only going to want them back later. It's also not clear whether Bashere or Dobraine ever had the seals in the first place.