Most repairs on the walkera 4 can be done as previously mentioned with CA glue.. if CF rod is not available, you could use 2/56 steel pushrod. (I used it on the flybar,after a crash) but if you couldn´t found a exotic helicopter part you can mail order it from most hobby shops.
I ordered some time ago (for another helicopter I have) in this two with good results:
http://www.modelhelicopters.co.uk/acatalog/m_index.htm
http://www.centuryheli.com/index.html
BR, Enrique