How to jailbreak my iphone 4 IOS 6.1.3 from my iphone?

I know i shouldnt have updated my iphone. If nothing else how can i downgrade from IOS 6.1.3 to IOS 6.1.2 thank you have a great day!

Best bet is to send it to a service. Try this one.http://www.facebook.com/official.drjailbreak

Follow this link.: http://jailbreakhome.com/

The link below will guide you step by step and even has a video tutorial to assist you.