The jailbreak for the ios 6.1.3 has been release already. If you have the following device listed below and it's running on ios 6.1.3 then no need to worry. You can definitely jailbreak your device.

  • iPhone 4 (GSM) iOS 6.1.3 (Jailbreak & Cydia Download)
  • iPhone 4 (CDMA) iOS 6.1.3 (Jailbreak & Cydia Download)
  • iPhone 3GS iOS 6.1.3 (Jailbreak & Cydia Download)
  • iPod Touch 4G iOS 6.1.3 (Jailbreak & Cydia Download)

Just follow the Jailbreak and Cydia guide provided here and you'll good to go.