Off Garlic! Can we fix recipe?
Unless your garlic has fungus growing on it or is badly discolored it's unlikely this flavor is from it. Garlic generally keeps very well and is still safe to use, and still flavorful even when it's a bit shriveled. 

It's much more likely these off flavors are coming from another ingredient, and could be a sign of some sort of contamination, in which case you should chuck it. Even if it isn't you can't get rid of the flavor, so my recommendation should be to get rid of it and order some take-out.