I installed new pads yesterday on my son's 95 Accord. The pad should come out sideways. Most likely the old pads got rusted and stuck there. I do not see how you can remove them using C-clamp. You need to pry them out. Probably with a scredriver or similar tool. Make sure you do not damage your rotor.
New pads should fit snugly. If not you will have to file/grind them.
Good luck!

Sam