The Travelin Man
What you need is adequate training from your supervisor. If that person does not see the value in training you correctly, then you might not be working for the right person. On the other hand, and I am not trying to be ugly here, you might be behind the expected learning curve, which might explain why management is not providing additional training — they just don’t believe that you will be there long.
You really should speak to your boss/manager about this.