MIDI Connect between Yamaha DGX-203 & G4 Laptop

I'm currently trying to connect my Yamaha DGX-203 to my G4 Laptop so I can use it in both Garageband and Sibelius, which I recently purchased. According to the Yamaha manual, I need to have XP Home Edition on my laptop to enable my keyboard to connect to the USB-MIDI Driver I've downloaded from Yamaha.com. Is there an easier (less expensive) way to connect the two? In the Sibelius manual they show that it's possible to connect the keyboard and computer through a midi interface. Would this be a cheaper option? Thanks for your help!