There's a link at the top of the page for DVC point calculations.
As far as paying for cash nights, you'll need to contact Member Services and ask how much the rate would be for the night you are looking for (if available). I'm not aware of anywhere MS cash rates are published.
You can get the rack rate through Disney website. Just type in your dates and choose the DVC property you'd like to stay. I'm not sure if AP discounts apply to DVC cash reservations but I don't see why not. And if you're a member, you get 25% discount off the rack rate if there is an availability.