I'll also agree with the 2-3 week timeframe, once again, depending on how much she's willing to wiggle it.
As to how much the toothfairy should leave. My 5 year old daughter has lost both of her front bottom teeth in the last month and a half. For both of them, I folded a one dollar bill into thirds, the long way and wrapped it tightly around a stack of coins and tape it. I go with 2 quarters, 2 dimes, 2 nickels, and 2 pennies. The dollar bill keeps all the change together, so it doesn't get lost under the pillow and then we can have a counting lesson to see how much she got. Comes to $1.82, but to a five year old, that seems even better than $2 in bills. Then as she gets older, and better at understanding counting money, I'll be able to mix it up, adding more coins for those harder to lose teeth, (I remember some of the bigger teeth hurting more when I was a kid and when my son was losing his teeth) or less coins, but show that they can still add up to the same. Hope this helps.
Merry Christmas!
P.S. J. read Heather's post about "forgetting" and wanted to add a funny story about my son. When he was about 7, he lost a tooth and opted not to tell M.. Well, he put it under his pillow and, surprise, no money the next morning. He came out and let M. know in no uncertain terms that he was "on to M.." Then he looked at M. and with big eyes and said "Please tell M. that you're not Santa Clause too??" That was when all of the childhood myths were put to rest. So, the next year I had another baby and we got to start over and he has a blast "tricking" his little sister into believing now!