Is there anyone else, besides the priest who can help you out? Maybe, they can use the materials and teach you on another night?
Remember, Lent is the busiest time of year for the priest, as well. There are all manner of Lenten services during the week, etc.
However, do approach him after Divine Liturgy. If there are other people...fine, get in line and wait. When you finally approach him, don't make him feel guilty....just tell him you are interested in becoming Orthodox and would like some instruction. Tell him the days you are available and then ask him if there's someone else whom he recommends to teach you, or if he has any suggestions on how best to accomplish this.
Most importantly, don't get discouraged. Remember, the more interested you become in Orthodoxy, the more interested and dedicated the devil becomes to keep you from doing so. Don't let him win. Be persistent.
Remember, the women who kept calling after Christ? She didn't take NO for an answer. Don't you take NO for an answer, either. Keep knocking, and the door will be opened.
Is the priest married? Maybe his wife can help you.