workout to put mph on my fastball?

[kkcountry]

just recently, while a friend and i were playing catch, he noticed something in my delivery and tweaked it a little bit. soon he had me popping the mitt and we got a hold of a radar gun, which had me throwing up to 85mph off of a mound. if i can do that in my sorry shape (6'1/2", 240 lbs, wide frame, lots of fat) i know i can get into the 90's if i put a little effort into getting stronger. well, what do you have for me?