Indeed, PostScript is the only viable option on the Amiga. If your Amiga needs to print, you need a PostScript printer or need to be willing to do the PostScript to PDF conversion to print on another machine. TurboPrint makes this process slightly easier.
Traditionally, a lot of LaserJets used the same or very similar drivers. I'm not sure if that's still the case, or when it might have stopped being the case. Give a different LaserJet driver a try - you might get lucky.
