Due to grain abosrption, it sounds like your boil off wasn't actually a problem, its about the usual 15%. It actually sounds like your problem is your efficiency. Based on your #s, I'm getting only like 48%. I'd go with the extra 2.5gallon sparge next time.
Also, it sounds like after topping off you weren't well mixed because your starting OG should have read around 1.046. Compared to what it was supposed to be this will be a little watered down, but it still sounds like it'll make for a good one.