This could take a while for you, I would start with reviews from this hallowed site, including mine - but there are many others:
http://www.ukgser.com/forums/showthread.php?t=247181
http://www.ukgser.com/forums/showthread.php?t=247181
Then grab a copy of the excellent "Motorcycle Journey's Through The Alps and Beyond" - should keep you busy for a few winter Sunday's.
Also grab a logon at:-
www.alpineroads.com once you have a better idea of what you really want to do and where you really want to go, and of course ask more questions here.
Route Napoleon Sucks IMO, Route De Grand Alps is far better, unless your in a car / camper van, or on a Harley

D)
Note the Alps is an odd L-Shape that has fallen forward 90 degree's, RN will take you to the south of France by the Italian Border, but getting to Austria via Italy in any sort of direct fashion means not taking Alpine roads.
To go from the South of France to Austria via the Alps involves working your way North a bit along the French Italian border (RDGA again) until you reach Switzerland where you can run along the spine of the Alps to Austria.
RDGA is about 2 days each way, and it is a full day of boring motorway to get to the start of it, and at least another two days back from Austria, that's 7 days if you don't mind packing up and moving on every day.
Personally I would do a smaller section, if you want to do the Stelvio then tie it in with a couple of other places, see my 2010 trip where I did mainly Switzerland stopping near Mont Blanc, Andermatt and Livigno (Stelvio)
You could also visit the Stelvio region and the Dolomites, or if you really fancy Austria the Grossglochner is where you wanna go:-
http://www.grossglockner.at/en/
And the Stelvio is sort of on the way.
Next year I am heading that way stopping at Andermatt and probably Bormio followed by a few nights in the Dolomites and a few more in Austria and then will return via a couple of nights in the Black Forest - that will be a fortnight trip.
Try to allow ten days for any Alpine trip (any less than six and I would say go somewhere closer to home) and don't forget the Alps is bigger than the entire UK mainland, with about 400 passes and would need about 8 weeks solid riding to cover all the good bits so your not gonna do it all in a week - and you don't have too, you could get a weeks great riding from a single base.