You can buy a pack of grease fittings and install them yourself. Just drill the appropriately sized hole (with a magnetic drill bit- ball joints HATE metal shavings
) and screw them in. With a little luck, fresh grease will shut them up and extend their squeaky little lives.
For future reference, you shouldn't pump so much grease in that it forces it's way out of the greasebag. That tears the greasebag and leaves a way for water and dirt to get in. Just pump until you see the bag swell a little. Unless the greasebag is already torn, in which case, the harm's been done...pump away!