Hello, My name is John Kells with
http://WWW.ADVANCEDART101.COM and I think that you have more problems then what meet the eye in your pictures. Please take a moment and research deep before going down this repair road.
I have 30 years of experience doing such repairs that other people built, and believe what you want, but, this is very serious if not done right. I will step by step what I see to be your cure if you want to go it alone.
#1 Chip out all concrete until it is clean and free of lose pieces. #2 Clean rust off of rebar #3 Drill 1/2" holes in the middle of the wall every 6" to epoxy in 3/8" rebar that will be 6" deep on each side #4 wash out holes
and concrete, allow to dry fully #5 fill 2/3 with epoxy in the drilled hole one level at a time, add steel with the extra length to allow for your crack span #6 Put a form on wall to allow for pouring your repair material
#7 Before it is dry, remove form to rough up the wall with a stiff brush so that the plaster sticks better ( wet down the old cement before adding new material to assure a good bond, and rub it in with your hand at the point
of bond to help even more ) I hope this is good enough of an explanation for you, good luck!