I must say, months ago when I first stumbled upon the bitcoin, I lost hope in ever utilizing it as a online payment alternative because of GPU+Power costs, and the fact that the value dropped greatly within 2 months (Back when I was concerned with profiting from it, alone).
May be you misunderstood how the bitcoin works ?
You don't need to mine bitcoins for using it as online payment system. You just earn or buy coins when you need them.