We "fixed" this issue when my DS was 4 months (and had got strong enough that things were hurting), so you certainly have time to do it.
You may also find that as bub grows it will be easier to get more in to his mouth!
Just keep trying - it may take a few days, but now you are aware of what you need to get to that's the first step.
Have you tried to just let him attach himself? Lie him on your chest in the general vicinity and let him wriggle his head where he wants it to go?? That can work pretty well too.
And making silly faces with a big open mouth can help sometimes.
good luck!