In some cases h/b does not show till 8 weeks. I hope you get some good news next week.
Did they do a vaginal ultrasound? I had an abdominal u/s at 7wk 3 days, they couldn't see much, so did an internal one, and bam! Bub was there clear as day, flickering heartbeat was seen. Unless your dates are out, bub should be visible by now. Hope all turns out well for you:)
Dont have advice as such, but the hcg sounds so positive, good luck, and keep us posted..