And if you can find the customer base that will let you bring in $7500 (if based on 5 days a week) per week then that is a great setup.
If your customer base are only used to paying $10 / week however, i would say cut your expenses... very fast... or take extra jobs for the remaining 37.5 hours (calculating with a 40 hour work-week
since you were only going to work for 30 min / day with retouching ;D
Jokes aside.. helen brings up a point. If your costs demand a higher hour cost than what your customers want to pay then you need to cut costs, exapand your markets, find alternative ways of income or such. Making money with a business is about juggling the money. Most of the time you need to be businessman first, artist second. And unfortunately it's too often the other way around =)