your metal is soo thin , its gonna be hard to stretch the metal that fare...
best bet is gonna make new panels or something or maybe cut a section out of your panels, bring it out some , then fill the gaps with extra metal..
heres a link of John Kelly making some fender flares... but if you notice 2 pics are the front of the car where he stretch the metal with a bead/sand bag and hammer, then smoothed it out will hammer and dolly..
http://allshops.org/cgi-bin/community/communityalbums.cgi?action=openalbum&albumid=9980138836765