@3picFail, you haven't provided enough info for anyone to help you mate..
Firstly, what fw is your PS3? If it's 3.56+ you're out of luck unfortunately, for now anyways...
Yes, there are downgrades but I think you need a dump of your 3.55 or less NAND or NOR and (again, currently), you need further kit and be good at soldering.
If you're on 3.55 you would need to downgrade to 3.41 and if you're on 3.41 the stick should work.
As far as you having a mac.. yes, many programs are windows based. To get around this you can either install bootcamp on your mac or VM Fusion or Parallels.
For simple one off programs you can even install Wine via Wine Bottler - which is a free download and pretty handy but you have to check which programs will work or not.
"We all agree your theory is crazy, but is it crazy enough?" - Neils Bohr