Well, let's try it this way; Generally, numbers are interpreted as single digits, so we'll have to split them up & see what kind of explanation they might mean combined.
'1' is a dream symbol of unity; oneness, wholeness, that which is indivisible, the self.
'2' on the other hand, means the equal sides of something. Opposites, contradictions, balance. Yin/Yang, female/male, micro/macro, those things which cannot exsist without their equal partner.
Please tell me if I'm right; are you or someone close getting married? Or is internal conflict involved? Either way, they could both illicit a '12' in a dream; the '2' people in a marriage becoming '1' / or '1' person internally diliberating an issue with '2' strong arguments for final decision.
Hope this helps.
Quizzy