If you want to fight the new Assault Weapon Ban from the Obama administration, you need to start writing your Congress people (House and Senate). I have included a sample letter you can adapt and modify as you see fit below:
Mr. [Congress Person],
I am writing to you to oppose any gun control measures from the current administration. Specifically, I am opposing any thought of a new assault weapon ban.
Attorney General Holder recently said that, because of Mexico's current gun violence, the administration will propose a new, permanent assault weapon ban. That is an illogical conclusion. The reason Mexico is having gun problems is because Mexico chooses not to secure its own borders against gun traffickers. The BATF is assisting Mexico by investigating and arresting gun dealers who violate the law, and that is good. However, to conclude that we need to constrain the rights of law-abiding Americans because of the ineptitude of the Mexican government is simply absurd.
Moreover, the firearm industry is providing many well-paying manufacturing jobs in the United States, jobs that are disappearing from the rest of the economy. If you support the Assault Weapon Ban, you will be destroying well-paying manufacturing jobs in your district, deepening this recession. You will be contributing to your own electoral loss at the next election.
Thank you for your consideration,