Where to start? My DS was diagnosed at same time as you and there is so much to learn.
Many people recommended Hanen book More than Words, which is a useful introduction and Starlight will be able to tell you about courses near you as she was offered one.
Ask for portage and speech therapy to start now, not wait until you have a diagnosis.
Look at all the options around you: private and local authority nurseries, mainstream and special schools, ABA providers etc. You have to find this out yourself, Local Authorities don't generally tell you about anything other than the cheapest option.
If you can afford ABA do seriously consider it - there is a Yahoo ABA website - you may be able to visit a family who do it - and go meet providers. It has been really positive for my son and I wished we had started it sooner.
If you want the Local Authority to pay for decent provision for under 5's you have to get a statement its the only way to access specialist provision which is what your daughter needs. Maybe not forever, but to maximise her progress now.
Expect things to change. Your child will still make progress and learn, but the autism may start to show itself in different ways as time goes on. My DS had few repetitive behaviours at 2.5 but by 3 they were really frequent and new ones all the time. We were told they would not try to place DS anywhere specific on the spectrum as children could change so much between 2 and 6. When he is 5/6 we should have a clearer idea and also whether his IQ is normal or not. Many experts say they wished that sensory issues had been included in the criteria as most children with autism will perceive things differently. Children can move up the spectrum especially when they are young. There is very little evidence to say which children will make good progress and which won't. What your child is like at 2 won't necessarily tell you how their autism is going to affect them later on.
For DLA / social services download guides from Contact a Family and Cerebra. Apply for everything, autism is an expensive business.
Go along to your local NAS group and meet other parents - they will give you the lowdown on which schools etc are good and which to avoid and about local services.
Talk to people. It can be isolating if your child isn't mixing with the others / getting left behind. Let those around you know whats going on.
Always ask on outings if they do a carers discount! I now go swimming for free when I take my DS.
Take time out for yourself / your partner. Accept any offers of help / babysitting etc.
Don't ever forget that parents are the only true experts on their child. We're the only ones who see them 24/7. If someone is describing a child which you don't recognise as your own, they've got the assessment wrong not you.
I have met many parents in the past 10 months who have told me how their children made great progress and how well they cope. There are horror stories out there, and often professionals are reluctant to talk about the future or offer you any predictions, or have low expectations, so it can feel as though things are gloomy. But there are lots of positive hopeful stories out there from parents who were once in your shoes.