I had a similar problem. I handled it by working in the field for 4 years after undergrad, made sure my letters of recommendation were from people who could speak to my abilities, took a non-degree graduate course, and spoke about my poor GPA in my applications mentioning the things I have done to set it right.
I think you should try to approach the situation very "matter of fact"-ly when you try to explain it. Just write (or speak) clearly about what happened. You aren't making excuses you are just stating what happened and that it doesn't correctly portray your abilities in the field. I would also check the requirements for the programs you are trying to apply to. Some have strict GPA requirements and will not budge from them, others have a cutoff but will accept under the cutoff in some circumstances, others do not have a cutoff.
I wish you the best of luck. I'm sure you will find and get into a great program.