Think they will have formed bulbs by now-try one and see. You could strip off the outer leaf if just one layer is affected-as long as the plant can continue to use its leaves for photosynthesis it will continue to develop. (I knew that college course would come in useful one day...!)
Same here...it's the lousy weather that's caused it to be bad this year. I lifted a bulb the other day and they're almost ready but I'll leave them for another couple of weeks just to be sure.
You'll get conflicting views if you google 'garlic rust' and they vary from just ignore it to never plant aliums in your plot for at least five years!!
As samantha says, don't compost the leaves. Best solution is to burn them but I just put mine in the normal domestic rubbish bin.