Even though you don't have a postscript compatible printer you can still make a postscript compatible file. Normally if you have a printer already attached to your system that is postscript compatible all you have to do is check the box that says "print to file" after you print a document to the printer. This will make a file that you can then use on xconvert.com to make a Portable Document File.

If you don't already have a postscript compatible printer you can still install the postscript compatible printer driver on your system as if you owned a printer. When asked for the "device" that the printer is attached to just select "file". Now when you print it will create a postscript compatible file.