Why would you want to get mixed up in this kind of baggage? I know it's not your fault, but you can control how you handle it.
She Should Take Care of The Problem
It is your girlfriend's responsibility to make sure that this guy leaves her alone. I know what she did would feel hurtful for anyone but if she really wanted to get this guy out of her life than she should be strong enough to do it.
She Likes The Attention
So I think that she doesn't really want to. If the attention from her ex really bothered her than she would have been straight with him about where he stands in her life.
She needs to be honest with him and let Al know that right now would not be the best time to "woo" her back.
You Can't Change Al
As for Al - you're right. He's hurt and is doing everything in his power (even using any excuse for her to feel sorry for him) to get YOUR girlfriend back. If he really did love and respect her than he would be gracious enough to back off. But you can't really do anything regarding his behaviour. Only Al can change himself.
Ask yourself this - Is she worth it? If she is, you may have to accept the fact that this ex would be hanging around her for awhile.
Let Her Go, Until She Let's Go of Al
Honestly though, this is her problem. I think until she can get rid of him, you need to let her go. Then it will be clear to her that Al is seriously bothering you. I think you'll get your answer regarding her feelings toward him. As hard as that may sound, problems need to be dealt with one at a time and soon.
Hope I've Helped,