I doubt you'll mine 10BTC in a week. With 70MHash I make hardly .05 a day.
I'm mining at around 500mh/s which pulls in about 1.5BTC a day. It shouldn't be a problem. I also have 1.5 in my wallet right now.
Why do you need it?
I'd like to make a purchase that may not be available in a week or even tomorrow.