A google on the number molded into the plastic base ALX072-03 pulls up a bunch of stuff labelling this battery as a Silverfish. None of the first page of hits in images, shopping, or regular show clearly that they sell the two-blade connector only, but I would bet that if you contact some of the places that sell the case, one of them might sell just that part.
I can see other parts that have molded in numbers, but can't read those in the image. If there is one on that connector itself you might see if it pulls up anywhere.
Another search on "silverfish battery plug" pulls up a bunch of things that look like it, in the image results.
What happened to the original connector?