Need help with final mixing, Digital Performer, MOTU 828, Roland XV5080 Options

[Noella]

I recently bought some equipement. I sequenced my song in Digital Performer 3.02. And then I recorded it using MOTU 828. I plugged in my sound module (Roland XV-5080) directly to 828. I checked the levels in DP and then recorded my song (in stereo). Everything works perfectly. My song sounds great! I exported my file as aiff and listened to it. I sounds very quiet. I made a copy of it and listened to it at work (good speakers) and it just sounds 'stereo.' The sounds sounded trapped.

So I went home and tried to use the surround sound settings in DP. Then I exported the file again. And it sounds the same.

Why is my soundfile so quiet and how can I make it sound better? Do I need to buy another equipement and program? Am I missing a step?