The case is going to trial at the end of this month. The attorney I initially hired to make the answer left out a few defenses... Could I mention this at the readiness hearing? or would it have to be a seperate hearing? The case is 2 weeks from trial and the plaintiff has yet to finish depositions... is that normal?

You cannot wait until the trial readiness conference to bring up this issue. The court will very easily deny leave to amend based upon prejudice to the other parties.

It is not normal to have pending pleading issues open and/or unfinished depositions two weeks before trial.