looking at that jamma convertor thing again, it looks like the arcade controls are expected to go into the PC via the very old style 25pin port (ie. serial or parallel port thing, i cant remember).. anyway, that's way out of date.
its a shame you didnt know about the JPAC, thats what u would have wanted:
... however, Sune makes sense by saying that if u dont plan to use an arcade monitor or old style crt tv, then u are better off purchasing any pc monitor/lcd tv/etc which accepts eg. 15pin vga input, and then use one of these below to take care of your cocktail table controls: