Unfortunately, the dependencies required for OBS aren't provided in the Debian sources until sid (unstable), which almost nobody uses (I'm betting).You should be able to add the ppa repo to your Debian installation.
http://www.binarytides.com/add-ubuntu-ppa-repository-to-debian-7-wheezy/
If you can't, you can check this out. Easy enough to make a package by yourself.
https://wiki.debian.org/CreatePackageFromPPA