I had one ultrasound done and my gestational sac measured 4w 4d and all we saw was the gestational sac and a possible yolk sac forming. I just went back Thursday (2 weeks later) and I am now measuring 6w 5d and this time there was a yolk sac, a fetal pole, and a heartbeat going strong at 143 bpm. As long as you HCG levels are over 2000 they should at least be able to see a gestational sac.
I had my first ultrasound at 5 wks 1 day and the dr saw the gestational sac and yolk sac - I go back in 2 weeks when I'll be 7 wks 1 day and we should see the baby then and hear the heartbeat!
How far along? 2 1/2 months? I just went in at 6 1/2 weeks and saw mine...I think you can see it as early as 5 weeks...