I would replace it now while it is easier to get to. These things don't heal themselves, and when the cracks get bigger at some point the alternator will fail.
If it were easier to change and you were willing to keep an eye on it it MIGHT be worth waiting, but that isn't the case here. Change it, and buy yourself some peace of mind.
As far as I know, all Contiques use a 130 amp alternator.
