well...not familiar with that make or model of toilet, but I just had to fix a leak on mine, and the problem was the ball valve. this is what turns the water on/off when you actuate those pedals. (I'm not sure what John means in his reply; the shafts/springs from the pedals on my toilet don't go into the bowl).
there are a couple of places where water "could" leak. the fitting on the ball valve where the water supply connects; the ball valve itself; the hoses that go from the other end of the ball valve and send the water to the tank and bowl.
the other thing I'm thinking: is it leaking, whether you use it or not? (i.e. water supply leak), or only when used? there is a rubber seal that goes around the exit-hole, where the stuff goes into the tank. I wouldn't think that would be very likely to leak, but again..your toilet is different than mine.
the toughest part of my project was getting the toilet out. there are 2 closet bolts with nuts that have to be removed; then the toilet just lifts off. BUT...one of those nuts is a real bitch to access. took forever for me to get it out...and another long cussing session to get it back on. yours might be entirely different, in terms of accessability. but its probably just a couple of nuts holding it in place. one of them is probably right in front, under/behind the pedals.