I wouldn't stress about getting weavile right now, ice isnt too important to have for raids (unless this is about gyms and you see dragonite/salamence in gyms all the time), but mamoswine is coming soon, and we will be getting guaenteed sinnoh stones on its CD and the weekend, and mamoswine is the better ice attacker.
If you have a personal attachment to weavile, I wouldnt tm the already evolved one as weavile seems to be have a much better job as a dark attacker compared to its job as an ice attacker