do you have a crank arm remover and bench vise handy?
i've been in your situation before. my cranks weren't exactly top of the line (or even middle of the line), so i wasn't worried about ruining them. if you like your cranks you may want to get a towel/rag handy as well. or you may want to just ignore this reply. the choice is yours.
step 01: remove crank
step 02: wrap crank in towel/rag if so desired
step 03: place crank in bench vise
step 04: fix pedal wrench to wrench flats on pedal
step 05: pull/push with all your might.
step 05a: make sure you're going in the correct direction.
step 06: if step 05 fails to work (which it did for me), consider using a breaker bar over the pedal wrench arm. or, if you dont have one handy (which i didn't), consider using a BFH* on the pedal wrench.
*BFH = big frolicking hammer