Star - I would ring around to your local radiographers. I had to travel 120km each way, but I got mine bulk billed with HCC bc it's xray based (as opposed to a hycosy which is u/s based).
There are lots of things that can be found in a lap that aren't STD based. ovarian cysts which can block the tubes, endo thin/thick lining. And I should add - when I had my lap beginning of this year the gyno did another dye test while I was out. So is that a possibility that you can get in done in one go saving you the cost??