They should pair up as long as the one you added wasnt the female from wherever you got it from. The one you had should be a female now since she was by herself for a few months. Since the one you added was small we can assume its male.
They should pair up soon but if they start fighting you may have 2 females so one would need to be removed or they would kill each other. See, clownfish can change from male to female, but they can not go from female back to male
29 gallon-planted community
20 long frag tank
75 gal-planted goldfish
75 gallon mixed reef with 20 gallon sump