Wow, net hashrate 2.2 GH/s? Some kind of supercoin just launched or what's going on?
Mining is not profitable, at least not for me...
My computer with an HD 7990 costs about 3,- a day to mine and the total coins that I've mined are not even worth 3,- after mining a full week

Same here. I mined with about 4-5Mhs from the beginning.
I would rather say that mining is not profitable with the current ERC/Euro rate. But who knows about future value of ERC? I keep the coins and after a year today's effort might be profitable.
BTW: How stable is your GPU rig? I use sph-sgminer under linux and crashes once or twice a day.
I also hope that the coins will rise in price, but who knows...
My computer is 100% stable. I'm using sgminer on Windows 7.
Do you also have an HD 7990? If yes, did you overclock, undervolt and what's the usual Mh/s you get?