I have the what to expect when your expecting book (my life saver I swear) and it gives a guide of levels but every woman is different of course.

Weeks of Pregnany - Amount of hCG
3 Weeks - 5 to 50
4 Weeks - 5 to 426
5 Weeks - 19 to 7,340
6 Weeks - 1,080 to 56,500
7-8 Weeks - 7,650 to 229,000
9-12 Weeks - 25,700 to 288,000

I didn't know anything about hCG levels anad all that crap till i read through the books lol