Sorry to hear about your loss. It sounds like you have a good bike, no worries with a 520. Next up is racks, luggage, and camping gear (if you're going to camp).
If you can afford it, Ortlieb is the way to go - I have four roller panniers and fully expect them to outlive me. Whartever your budget, don't buy cheap luggage or racks (expecially racks).
Browsing the forum here is an excellent way to get your bearings, as is
Crazy Guy on a Bike - I suggest you browse the journals there. There are also a lot of worthwhile cycle touring blogs out there. (Keep an eye on people's sigs, you'll pick up a few links that way ontop of what you can google.) Feel free to browse my
touring bookmarks as well.
Machka started a thread about
positive experiences with vendors you might find useful.
Emkbarking on a life-changing experience like this is a very healthy response to a loss. Touring can be a wonderful and, at times, transcendent experience; I wish you the best of luck.