I am all new to the bitcoin world and  i would like to start mining. I know this isnt the gold rush anymore and that the good days are over but i am still interested in mining even if i dont make money out of it. To start off I would like to mine 0.1btc per week. I think this should be doable. But this is where i need help, I am not sure how much power i am gonna need to do it. I mean how many gh/s. I would then buy something appropriate.

I know computers cant really mine anymore but im gonna leave my specs anyway just in case.

Amd phenomII 965 deneb. Quadcore 3.4ghz
Nvidia geforce 650 ti boost superclocked.

So if anyone can help me calcukating the power i need! Thanks!