It's great to hear that you got your hands on Hotel Dusk. Of the two you want to venture into, I would recommend Ace Attorney, but Trace Memory is also a good game since it was developed by the same people that developed Hotel Dusk. So either way you go, you won't be disappointed.

If you plan on starting with Ace Attorney, I would recommend getting the first game, Phoenix Wright: Ace Attorney, as your first game in the series. It'll probably be very hard to find, but the best of luck on your search. You'll best get it online somewhere.