Family Portrait Pricing?

Last weekend my wife and I shot a close friend of hers family. 2 kids and a husband so 4 total. We have about 20 very strong images to give them. We took about 150 or so images. On average I am spending about 10 minutes per photo editing. Her friend saw 2 images that had a fast edit done. She is now interested in us shooting pics of her family. So now I have to figure what to charge. I would expect at least $30/HR. The wedding photogs here start at about the $3000 range on up. The very good ones are about $5000 to start. I think asking $300 for about a 1-1.5 hour session would be fair? Any ideas??????
THANKS

This is a sample of 1 of the images from the session with her friend. Just Curves done to it!

I went to a seminar last night, a good, experienced portrait photographer here in NZ charges between nothing and $100 for a sitting fee, about US$250 for a 5x7" print, US$450 for an 8x10" print, and $2K for a 30" canvas. He does his portraits on the beach, in a park, etc. He said his average sale is about $1500, but he's had sales of between zero and $12,500. These figured are fairly typical for good, experienced photographers, but a newbie probably can't start out at these rates.

Just one comment on that image, if you use off-camera flash with one diffused light to the right the image would have much better lighting, and it'd have avoided or reduced the shadow of his ears on the fence behind him. Meter the camera for one stop below ambient and set the flash to one stop up, that way ambient becomes your fill light.