Shell: Sed -i.bak to rename file by appending current date -

i have sed statement replace few contents in file. taking backup copu name file.bak before replacing content.

sed -i.bak -r "s#^(.*/abc_def_app/).*(/application1\.war.*)#\1$version1/$version2\2#" /path/file 

but want file backed current date. file.071913

how can it?

as have

$ date "+%m%d%y" 071913 

what following?

sed -i.$(date "+%m%d%y") -r .... file