you might be able to undo the bottom shock nut then jack up on chassis, push axle down and slip the old spring past it and the repeat in reverse for refitting. bit of a pig but worked on mine once.
i found laminate floor underlay was good when i had the van top on, nice and light so stayed stuck to the roof and it's dirt cheap. cheaper still if you can find a roll in a skip like i did.:D
if you put your location in you may find someone willing to weld new brackets on for you aswell. i'd be inclined to check the rear prop uj's aswell once its repaired as it might have pulled on the yokes or spiders .
You can buy weld on replacement brackets, i would avoid driving it at all like that but if you must then try to secure it to the rod somehow, maybe with big ratchet strap or such like and limp it down the half mile as slow as possible.