Arrest her ass, duct tape her and throw her in the cloak room.
You don't need the cloak room: I understand the Capitol has its own nifty little JAIL. Seems to me the best thing to do is call Lerner back for another House inquiry, and if she still refuses to testify, call in the Honorable Paul D. Irving, the Sergeant at Arms of the U.S. House of Representatives, and a couple Capitol police officers, have them take her into custody for implicit contempt, and then immediately perp walk her to the Capitol jail. She could be held there until the next Congress is seated (next January).
I'd love to see what Eric Holder would do next....
Just a thought....