ARD is a good resolution for it will result in the charges being dismissed and allowing you to have the case expunged. You need to speak to your attorney and find out if a payment plan. If it is not possible, maybe the hearing date can be pushed back.
I agree that you need to talk with your attorney; I strongly suggest that you do so tomorrow morning. If you are informed that he is still in trial or otherwise unable to speak to you at that time, explain your situation to the secretary or another attorney in that office if there is one. A lot of what you set forth I am in no position to explain, but I certainly think that you are entitled to a reasonable and understandable explanation. I practice in the western part of the state and can't help answer your questions regarding procedures and how you the defendant would normally receive notice of a court appearance. The way you describe learning of the hearing is absolutely not standard operating procedure. Whether the court system or your counsel dropped the ball or there is some other explanation for your lack of knowledge I can't even speculate. Although the ARD program is a creature of statutory law, it is by definition administered by the District Attorney's Office in each county. I don't know Lackawanna County's ARD program but I am confident that you will be able to set up a payment plan with the Clerk of Courts. Unless you get a definitive answer from your own attorney that you will not be required to relinquish our license at the hearing, be on the safe side and have a ride available.
You do need to sit down with your attorney. It sounds as if you have many questions and they cannot be answered or addressed on this site. It sounds as if your offense was DUI, although you do not have it posted. All counties do this differently. Again, try contacting your lawyer in the morning. Good luck to you.