If they won't pull out then you have to drill them out.
start off with the smallest drill bit you have working up to one thats slightly smaller than the pin. once you've done that they should come out with a bit of wiggling/twisting.
It sounds easyer than it is unless you have a pillar drill, but it is possible with a normal drill and top quality drill bits if you take your time.
I couldn't find replacement pins for sale anywhere but found vp dx style pedals (vp555) have the same size pins fitted and cost about £6-7 on ebay so i got some of those and cut the pedals off the pins if you know what i mean.
