Debunking Another Obamacare Lie...

Great news Micheal Reagan and Tom Cotton, you do not need an amendment, the law already requires that! Of course anyone with the Google machine could easily figure out that is a lie. Not only is that a lie but Congress and their staff are specifically instructed to purchase their healthcare from the exchanges.

From USA Today
the law requires congressional members and their staffs to get insurance through the newly created exchanges, so they are not exempt. In fact, the law prevents them from getting insurance through the Federal Employees Health Benefits Program, like other federal employees
Of course if USA Today is too in the tank for Obama for your liking, perhaps you can read directly from the memo from OPM instructing Congress  on what is and is not an acceptable healthcare plan under the ACA changes.
the health benefits plans for which OPM can contract under chapter 89 are not “created under” the ACA, nor are they offered through the Exchanges. Therefore, Members of Congress and congressional staff who are employed by the official office of a  Member of Congress may no longer purchase the health benefits plans for which OPM contracts under chapter 89. As part of their service, they are limited to purchasing plans from Exchanges.  This proposed rule implements this mandate.
Anyone who tells you there's a congressional "exemption" from the law either doesn't know what they're talking about, or assumes you're easily fooled into believing nonsense.