How can a 2 column text frame be split into 2 separate text frames?

Hi InDesigners,

I have a 12 spread (22 page) document that was originally created with a single column primary text frame in CS6. It contains text and anchored images throughout the doc. (images are anchored to the text frame).

My client now wants each page split into 2 columns, but the columns need to have different widths - the left column needs to be narrower than the right. Although I can create 2 columns in a single frame, it's not possible to adjust the column widths separately, so I need to get them into 2 separate frames.

Is there a way to convert a 2 column text frame into 2 separate text frames, so I can resize the column widths invididually?

kind regards,

-c