Hey There
It's also tough to help with the language difference - but I would also recommend building up your social media and even become active in various communities. I have found these two avenues to not only help my company site, but to also generate the best form of leads. I experience pretty poor leads from organic search actually, and the best from referrals, social and networking online.
It looks like you so some nice work based upon your portfolio. I'd see if you can leverage some of that for things like case studies which is content you can post on your own site and spread with social.
Hope that helps!
Sorry for the delay here, was on vacation. But let me see if I can help.