My first question is about your gpa -- is that based on a 4.0 scale? If so, one 'B' is hardly cause for worrying about your grades slipping!
I am not a doctor, and I don't even play one on TV!

However, I'm ADHD and my 11-year old son is ADHD, and we've run the gamut on meds -- especially my poor boy. At any rate, as far as the meds go, my gut feeling is that Adderall and Provigil together would be UGLY at best. I know Provigil isn't a stimulant per se, but it is some sort of 'alertness' drug. My son was on it for two whole weeks, and it was a BAD two weeks. He stopped tolerating stimulant meds last year, which prompted his old doctor to decide to try the Provigil. In his case, it was all the bad parts of stimulant meds without any of the good -- he was edgy, hyper, and couldn't sleep. I can't even fathom adding a stimulant med on top!
HOWEVER, the important thing to remember is different drugs work for different people, and apparently sometimes they stop working, too. I, myself, have been on the same dose of Adderall XR since Adderall XR came out. The only thing that has changed about my meds in ten years is going to Adderall XR from regular Adderall. My son stopped tolerating stimulant meds last year, and we've struggled finding something to help. He's taking a combination of Strattera and Focalin, much like Shane, and while it isn't perfect, he's doing much better.
At any rate, this is my long, rambling way of saying that you may not need more meds -- you may just need some stress coping skills. You may indeed need something in addition to the Provigil, but I'd be extremely leery of that something being Adderall or another stimulant. You may need a different med alltogether!
Whatever you do, keep talking to your doctor and your therapist and remember that there is no magic pill. I'm almost 40 years old and I'm disorganized, impulsive, hyperactive -- and that's with the meds! *LOL!!* I'm also reasonably bright, a good mom, a loving (if sloppy and not exactly domestic) wife, and absolutely contented and happy with my lot in life!

The meds let me sit still, and they let me finish tasks I start, but they don't exactly take away the ADHD. I honestly don't believe the med exists that will take those 'bad-ADHD' days away, but I do believe that the meds let me succeed in this farmer's world.
One last thing and then I'll shut up -- in college, I remember when I got my first 'B' and it drug my perfect 4.0 down to a 3.97 or something like that. I called a friend and bawled my eyes out! I'll never forget...she said to me, "So, I guess that means you'll be taking the bridge across the Mississippi with the rest of us imperfect beings then, instead of walking across on the water?" *LOL!!*