Yes, if you at least have a way to boot into Work Bench, you can use ADF2DISK or what ever to transfer those ADF's back to floppy.
To do that you'll either need, internet, a parallel network, flash card and PCMCIA flash card reader, a CD-ROM for you 1200, something to that effect. Screw the cat weasel, there's no reason to have that if you've got a real Amiga, that is if you just want it to read and write Amiga floppies anyhow.
As for using an ATX power supply. Yes, I'm sure you could go and buy an ATX to AT converter, which I'm sure you can find cheaper than through an Amiga dealer at that!
If you can, avoid Amiga dealers like the plague, as many of them will over charge for something even though it may not be Amiga specific. I'm hoping the reason for these high prices is because Amiga stuff isn't made in sweat shops, but how knows? That at least would validate the costs. Anyhow...
...what you should do, unless you are REALLY REALLY picky, is just pick up an old AT power supply, I'm sure you can find a dead classic PC somewhere with a 200 Watt pack or better around somewhere.
Take that, cut the cable on your original 1200 power pack and make your own, it's really really really really really really easy! I'm pretty sure I learned how to do it from this:
http://main.aminet.net/hard/hack/ExtraPower.lha And it worked, I didn't even use testers, infact I couldn't find a power pack laying around that did not use the universal color standard so I felt I was safe.
Plus as you can see by reading the docs, the dude was fried when he wrote the docs, so you know if it can be done while high then a 5 year old has to be able to do it too!
Also I picked up a VERY NICE adaptor cable built for such purposes. It looks quite nice, but again will cost you I think $15.00 plus shipping. With it you can at least spare your 1200 power pack (why anyone would care I don't know), but alas, I forget where I got it.
