Don't prune the bush down. Take the berries off if you want the best root and top growth this yr. The bush needs all it's leaves to grow roots and more top.

It will probably do alright leaving the berries on at this point if you keep it well watered. To really help the bush the berries should have been removed before you bought them. At this point the berries look nearly full size so removing them probably won't do much one way or the other.

Ok thanks fruit nut