The antennas are a commodity item. You can get them dirt cheap at your least favorite online retailer. The connector is most likely a uFL type. You could also d

The antennas are a commodity item. You can get them dirt cheap at your least favorite online retailer. The connector is most likely a uFL type. You could also ditch the connector and solder the antenna lead directly to the board. Outer grounding braid goes to ground, inner conductor is the signal.