You can use any WorkBench disks regardless of PAL/NTSC. They contain software for both I believe. Not 100% sure about 1.3, but 2.0+ do. Ask the seller. OldSoftware.com is likely to have several versions.
If you get a disk image from the net or Amiga Forever, and don't have another Amiga with a CDROM or ethernet, itll be quite hard getting the image to an Amiga floppy. I'd recommend buying a set online such as at that link, ebay, perhaps AmigaKit.com (in England)... or maybe someone here can send you a set.