Have you considered a private ultrasound? We had one at like 16 and a half weeks and it was one of the most amazing experiences I've ever been thru. It was so cool to just watch little Phillip move around, suck his thumb && play with his junk haha it's so much better than an ultrasound at the doc because it's for fun so all the time is spent just watching the baby, rather than measuring this, checking for this, etc. I totally recommend it it's in your budget. Ours was only 60 something bucks and I would have paid twice that! It's such an amazing thing, the look on hubs face was priceless and I'll never forget the experience
ps- i just looked at your sig, our heartbeats were almost the same exact rate at the same exact stage of pregnancy. we were at 124 at 6w2d .. if I believe the old wives tales, I'd guess your growing a boy... but i don't believe them