Merging 2 similar models into one

so i have one model that is rigged and everything but uses an old mesh

and i got another model that just has the new mesh without anything else.

how can i combine this 2 so the weights and skeleton is transfered to the new mesh?

propper model: http://i.imgur.com/v2Itj6I.png

wrong model: http://i.imgur.com/efmkmAm.png