Mumfun, I agree with the advice already given about getting a formal diagnosis and as much expert opinion as possible.
I have Asperger syndrome. I'm a married mum with a job. I've had to learn everything with no help at all for most of my life, and I won't say it was easy.
What would have helped me? Easy: Other people realising that they had to 'meet me half way', rather than making me (the one with the disability) do 100% of the hard work all the time whilst they carried on as normal or mocked me for the things I can't do. I'm really happy to help people by doing what I can to fit with their needs, but what helps is when people realise my differences and respect them. So, the school should be doing whole-school approaches to disability issues, teaching difference and respect and friendship. And enabling the friendlier children in the class to know how to include someone whose social skills are different.
In turn, a child needs to learn what other people do and don't find rude. This is hugely difficult for us, and even now I'm likely to get it wrong, as things that are 'just obvious' to others (body language, tone of voice, facial expressions, turn-taking in conversations) are completely invisible to me most of the time. That's why it needs to be a joint effort between the child and everyone around them.
We can't hear against background noise of other voices, we can't see if there's flickering lights in the room. We can't concentrate if something feels scratchy, tight or uncomfortable. Perfumes are chokingly strong for us. Those are generalisations, but they're often true. An average classroom is a battle zone for us because of all of this, not a place of learning. It needs structure, quiet. We need to be able to 'take time out' and just unwind from time to time, to think about the huge amount of information we receive from our senses all the time.
Who to tell, and when? Very much a personal decision, especially if there's no formal diagnosis yet. Go with your instincts. People's reactions are often not very useful at first (they're too busy denying it or being shocked!), so it's good to have all the facts to hand before you tell others.
Books? Have a good look at the recommended books on the National Autistic Society site, or Jessica Kingsley Publishers site. Find the ones that appeal to you, and have a good write-up about them. I like the Tony Attwoods, but some people don't. It's worth reading Freaks Geeks and Asperger syndrome for an insight into a child's life. Written by a teenager with AS, but he talks about life as a child and it's well worth reading (and very funny) (and no, I'm not on commission )
Keep asking on here - people are great.