Exciting news cat ! I remember being both nervous and excited, and quite terrified when we finally got our appointment at the fertility clinic. It can vary a great deal depending on where you are, but the sort of things we covered were:
Cost - eligibility for NHS-funded treatment is a post-code lottery. Though there are NICE guidelines which are well thought-out and mostly fair, hospitals aren't obliged to follow them and so each part of the country seems to have its own rules. Factors include age (eg many refuse over 40s, others have a lower threshold), weight (eg most refuse those with BMI over 35), how long you've been trying (usually 2 years), and whether you have previous children (some count stepchildren, others only count full biological kids of both partners). In some areas you'll get one round funded, in others 2 or 3. Some will cover the cost of keeping frozen embryos, others not. You should be told their rules at the initial meeting and so know if you'll be funded or not.
Tests - You should bring all test results with you if you have copies - and if you don't, make sure you start keeping them. I have a folder with copies of all my & DH previous test results going back 2 years - I can't say I understand ALL of them, but it's been essential (for us particularly as we've been to several different clinics/hospitals). These will probably be your hubby's semen analysis, and possible hormone tests, your hormone tests, including day 3, day 21 (or 7 days post-ovulation if you have an irregular cycle), LSH and AMH levels. If you haven't already had a HSG (Hysterosalpingogram) they may send you for one to make sure your uterus and fallopian tubes are fine. They usually also do HIV and STI tests, as you need to have these done before any treatment can be authorised. If you're missing tests I would suggest you push for as many tests to be done concurrently as possible, given possible waiting lists - otherwise you risk having to wait months for one, inconclusive results, and then months for the next one.
Forms - you'll probably have to fill in lots of forms about your health, background, sex life (not kinky details, just confirmation that you have actually been trying!). There's also one on child protection, which is just a tick-box exercise for them to cover themselves.
Treatment options - they might already be able to give you an idea of what treatment would be available. I haven't tried Clomid or IUI (insemination), as it wasn't suitable for us. Also, as it has such low success rates and for many can seem a waste of time once over 35. But perhaps worth seeing what they recommend.
Gosh, I realise that's probably a lot to take in! Most importantly I would write down any questions you have in advance, bring the notebook with you and make note of everything they say - make them slow down if necessary. You've waited a long time for this, and you don't want to be leaving confused or unsure. They should be used to this and be patient with you (but if not, still tell them to slow down if you need to!). If they send you for tests, make sure you understand what they're for, what the results will mean, and what the next steps would be. Also ask about timelines - it's a killer when you take a test and then realise you have no idea when you'll get the results. You can end up worried they've been lost somewhere, but unsure whether you can call and chase them up yet.
Best of luck!