I have original retail discs of xp from 2005 so all I do is buy a used motherboard with parallel port. Good option if you can find xp on disc.
Other than that:
I have a uc300eth controller now, works with mach3/4 & ucnc.
If the gecko just needs a normal step/dir and relay on/off style signal etc via the parallel input. I would suggest a UC400eth and idc26 to db25 cable on port1 then just have to figure out your pin no's.
You could then use a cheap bob on port2 for your spindle controls.
Be cheaper than say a smoothstepper and more reliable than going to a USB type controller.