My Daughter needs advice!!

My Daughter is a wedding photographer and uses 7D and a 50D. At a wedding last week her 50D crapped out!!
Her delima now is
Buy a second 7D body
Buy a 5D Mk2 body
Buy a 5D Mk 3 Body

Her only full frame lens is a Sigma 70-200 f2.8
Her normal lens is a Canon EF-S 17-55 f2.8

She has been told on some women photographer forums that the 5D Mk2 is bad autofocusing and the Mk3 is the way to go! It's a lot of money!!

Any advice would be greatly appreciated.
Thank You
--
There is no one so lonely as a person without their PENTAX........I said that!

http://www.pentaxphotogallery.com/edwindukes