There seem to quite a few math websites, you can check the two above. I don’t know how good any of the sites I listed are…I just gave you the links I found in a search
For English, if you want to get good, just practice reading and writing. Pick up books you like and read, read, read. Make lists of words and phrases you like you want to research. When you practice writing, get some one to proof read and help you edit. Just like reading, the more practice you get, the better you get. If you don’t have someone to edit, after you write, wait a day or two and read over it. As you read over it think, does this make sense? How can I improve it? If you don’t think you can improve it, you may need to give it more time and read it again. Even the best writers find ways to improve their writing…in fact they can be the worst critics of their own writing.
I put a link the Ontario Curriculum documents. I don’t think you will find a free website that has all the content nicely organized for you. Try looking at the curriculum documents and use that as a reference to research material. Ideally, you should find textbooks in the library or some other resource but if you are really in a pinch you might be able to use the curriculum documents. I know they can be confusing but some parts can provide guidance.
The last link, I’m not sure if it’s any good. I just stuck it there in case you might find it useful. Sorry, I couldn’t find a single, clear, well organized site. Hope this helps.