Extended Warranty - I just bought it with the car, can I return it and buy it later?

I bought my Certified PreOwned Prius yesterday and also purchased the extended warranty (7 years/100,000 miles). I know I was being somewhat suckered. What I didn't know was;

1. Could I have bought the warranty anytime within the 3 years/36,000? (or did it have to be at the same time as the car purchase) - they didn't explain this well.
2. If this is the case, can I return it? (I remember briefly mentioning they can refund the warranty)
3. And then if I decide to buy it again, within the 36,000 miles/3 years, will it be the same price or more expensive or what?

 

Interesting. However, I've decided to keep it for peace of mind and lack of hassle. At my dealership it costed me $1630.

How do you buy the warranty "here" however? (This is a store?) I thought you could only buy it from the dealership. Then, would it be considered a 3rd party extended warranty? or is it the legit Platinum Coverage or whatever?